Back pain is one of the most common reasons people take time off work and school¹. In fact, it’s the number one reason for missed days at work. Back pain can suddenly hit or come on slowly and can impact both sides of your back.
Back pain is no fun to deal with and can be caused by several conditions, including problems with your internal organs. Here you'll learn which organs cause lower back pain and why it can be felt on either side of your back.
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It can be a little confusing when you experience pain on just one side of your lower back. The pain you're feeling may be due to something minor whereby your body can rectify the problem on its own, or it may be an indication of something more serious.
Unilateral or one-sided back pain is a relatively common problem. When you experience pain on either side of your back, left or right, it may stem from issues with the organs in your pelvic, abdominal, or mid-back area. The pain may indicate inflammation, irritation, or infection.
The organs that are typically associated with this type of back pain can include:
Many abdominal or pelvic structure problems can occur and lead to one-sided back pain. Below you'll learn which internal organs can cause you to experience lower back pain — whether it's on the left side or the right side.
There are several types of kidney problems. Two common issues that can lead to lower back pain are kidney stones and kidney infection.
Kidney stones can lead to lower back pain on either side or both sides, between your hips and ribs in the back of your abdomen. This is referred to as flank pain. Over half a million individuals² wind up in the emergency room each year because of kidney stone issues. There's an 11% risk of kidney stones in men and 9% in women².
Kidney stones can make it painful and difficult to urinate while the stone is moving through your kidney, ureters, and into your urinary tract and bladder. During this process, you may also feel lower left back pain. You may experience nausea and/or vomiting and may notice blood in your urine.
Kidney infection or acute pyelonephritis (APN) is a severe type of urinary tract infection (UTI). Each year there are around 250,000 cases³ in the United States.
You may experience intense or dull pain on the left side of your lower back if your left kidney has an infection. Kidney infections typically begin in the bladder and urinary tract and spread to your kidneys. This causes kidney pain and inflammation. You might also experience other symptoms, including:
Stinging or painful urination.
Pain is generally felt above the hip, next to the spine, and tends to get worse with pressure or movement.
Your appendix is a small pouch extending from your colon, in your lower abdomen on the right-hand side. It can become inflamed or infected with a condition called appendicitis. Appendicitis affects around 233 out of 100,000 individuals and occurs typically between the ages of five and 45 and is more common in males.
You may experience lower right back pain if your appendix becomes inflamed, ruptures, or starts to leak. Subsequently, you can experience sudden-onset lower right abdominal pain, potentially in conjunction with nausea, vomiting, and fever.
This is a type of inflammatory bowel disease (IBD) marked by persistent large intestine (colon) inflammation. Around 3 million (1.3%) of individuals in the U.S.⁴ reported receiving an IBD diagnosis (either ulcerative colitis or Crohn's disease) in 2015. Lower right back pain can occur from the frequent abdominal cramping experienced with ulcerative colitis.
Other symptoms you may experience include:
You may experience pain in different locations, such as the rectal area or your abdomen, depending on where you have inflammation. For instance, some individuals may have left-sided, moderate-to-severe abdominal pain if the ulcerative colitis affects the lower segment of the colon and rectum.
Also known as distal ulcerative colitis, this only affects your distal colon (the last portion of your colon). Your distal colon extends up your colon from your rectum and stops at the point where your colon bends (the splenic flexure). The distal colon is the location most commonly affected by ulcerative colitis⁵.
As the name suggests, left-sided colitis affects your colon on the left side.
It produces symptoms that mimic some types of ulcerative colitis, including abdominal pain and diarrhea. There's no cure for the condition, but there are treatment options that can help reduce the symptoms.
Small ulcers can form in your colon lining because of the inflammation. They create pus and mucus and can cause other symptoms. You can continue experiencing symptoms throughout your life after receiving a diagnosis.
Gallbladder dysfunction or inflammation is generally characterized by severe indigestion, especially following meals. It usually leads to right-sided back pain and upper right abdominal pain. Around 14.2 million women and 6.3 million men⁶ between the ages of 20 and 74 have gallbladder disease at any one time.
Various pelvic reproductive organs in women can cause lower right back pain. For instance, one common condition that can lead to sharp, sporadic pain in the pelvic area is endometriosis, which can radiate to your lower right back. Approximately 190 million (10%) of reproductive-age girls and women⁷ worldwide develop endometriosis.
Endometriosis occurs when you have cells that resemble your uterus lining growing outside your uterus, commonly on the ovarian or fallopian tubes. They can bleed and swell each month while you're having your period, causing pain and other problems.
The most common symptom is pain and includes:
Extremely painful menstrual cramps
Pain during sex
Lower back pain
Painful urination or bowel movements during your period
You may also experience:
Spotting (bleeding between periods)
Digestive problems such as diarrhea.
Uterine fibroids are benign pelvic tumors that are common in women. A study shows around 4.5% to 68.6% of women⁸ develop uterine fibroids, depending on diagnostic methodology and study population. However, these estimates may be low since there are also asymptomatic women to consider.
Fibroids are tissue masses that develop around and in your uterus. They can lead to pain in the lower right side of your back as well as other symptoms, such as:
Pain during intercourse
Lower abdominal bloating
A full feeling in the lower abdomen.
Liver-related pain may be caused by an abscess, inflammation (hepatitis), liver scarring (cirrhosis), hepatocellular carcinoma (HCC), or a failing or enlarged liver.
Symptoms you may experience include:
Pain in your back or upper right abdomen
Lack of appetite
The pancreas is an organ in your abdominal cavity that produces enzymes that aid in food digestion and hormones that help control your blood sugar levels.
According to The National Pancreas Foundation, up to 12 out of 100,000⁹ people will have chronic pancreatitis each year in industrial countries. Overall, 50 out of 100,000 individuals will develop this condition. It frequently occurs in individuals in their 30s and 40s, and more men than women develop this condition. Common causes of pancreatitis include alcohol use and gallstones.
In this condition, the pancreas becomes inflamed, and this can lead to upper abdominal pain that can spread to your left lower back quadrant. The pain may feel like a dull sensation that can become aggravated when you eat high-fat foods.
The abdominal aorta is the main blood vessel that branches off into multiple smaller arteries that supply the belly cavity and legs. This vessel can grow abnormally large - a condition called an aneurysm. This usually occurs in older patients with high blood pressure, especially those who smoke, and is more common in men.
The aneurysm can tear open, a condition called a dissection, causing large amounts of blood to leak into the abdominal cavity. It usually causes severe and sudden abdominal and low back pain and can feel like a ripping sensation. This is a medical emergency and needs immediate medical evaluation.
Most back pain caused by sprains or overuse tends to get better without treatment within a few weeks. Over-the-counter pain relievers and/or heat or cold application to the painful area can help decrease your back pain. Bed rest is not suggested.
However, there may be other causes that require attention and treatment.
When to see your doctor
Call your doctor if your back pain doesn't get better after treating it at home for a week. It can mean there's a bigger problem that the doctor needs to evaluate. You'll also want to call your doctor if your back pain:
Spreads down one or both of your legs, particularly if you have pain extending below your knee
Is intense or constant, particularly when you lie down or at night
Occurs with redness or swelling on your back
Occurs with unintended weight loss
Causes numbness, tingling, or weakness in one or both of your legs
When is lower back pain an emergency?
While rushing to the emergency department is probably not something you want to do, you need to take back pain seriously — left side, right side, or both.
When suffering from severe back pain, a visit to the ER is recommended. It could indicate a medical emergency. Some red-flag symptoms of back issues that may indicate an emergency are a combination of any of the following:
Inability to stand or walk
Sudden loss of sensation in your genital and groin area, one or both of your legs, and/or your anal region
Loss of consciousness
Inability to control your bowel movements
Sudden, intolerable lower back pain or pain in your leg(s)
Back pain following a trauma, such as a sports injury, a fall, or a car accident
Uncontrolled bladder movements or difficulty in passing urine
Back pain radiating to your front abdomen
Sudden pain in the back with known fracture risk factors, such as osteoporosis
Many of these symptoms are related to cauda equina and/or spinal cord tissues in the lower back, organ-related damage, severe spinal nerve damage, or a potential fracture. It's important to have your doctor evaluate and treat your symptoms right away to avoid disability and permanent tissue damage.
If you experience any of the above symptoms, visit the emergency room immediately or call 911 if you're unable to get to the emergency room on your own.
To give you a lower back pain diagnosis, your doctor will perform a physical examination first and assess your back for any noticeable problems and see how well you move. They will also review your medical history, covering your symptoms, the severity of your pain, any previous back problems, and any recent injuries. Usually, the medical history and physical exam are enough for doctors to diagnose the cause behind back pain. But, the doctor may order some tests, such as bloodwork, X-rays, CT scans, and MRIs.
There are many possible causes of lower right or left side back pain. You shouldn’t hesitate to call your doctor if you're experiencing persistent pain that doesn't go away or a sudden, sharp pain that can indicate a serious problem.
Low back pain fact sheet | NIH: National Institute of Neurological Disorders and Stroke
Kidney stones | National Kidney Foundation
Data and statistics | Centers for Disease Control and Prevention
Endometriosis | World Health Organization
About chronic pancreatitis | The National Pancreas Foundation