Kidney Pain

Medically Reviewed by Michael Dansinger, MD on November 06, 2022

What Is Kidney Pain?

Kidney pain is discomfort that comes from the area where your kidneys are. It's often described as a dull ache, you feel in your sides, back, or belly. But pain in these areas isn't always a sign of a kidney issue. It's easy to mistake kidney pain for ordinary back pain. But there are some differences in how kidney pain feels and where it's located compared to back pain.

Kidney pain has many possible causes, and some could be serious. It's important to let your doctor know if you notice pain that you think may be coming from one or both of these organs.

Where are your kidneys?

Your kidneys are two small organs shaped like beans. You have one on each side of your body. They're each about the size of your fist. They're below your rib cage on both sides of your spinal cord.

Your kidneys have important jobs. They clean out water, acids, and waste from your blood. They make urine so your body flushes out the waste. If they're diseased or damaged in some way, they can't do their work to maintain a healthy balance of salts, minerals like calcium, and water in your blood.

Your kidneys also make hormones that help you manage your blood pressure, keep your bones strong, and make red blood cells.

So it's important to watch for any signs of kidney disease or damage, like pain.

Symptoms of Kidney Pain

Kidney pain symptoms include:

  • A dull ache that's usually constant
  • Pain under your rib cage or in your belly
  • Pain in your side; usually only one side, but sometimes both hurt
  • Sharp or severe pain that may come in waves
  • Pain that can spread to your groin area or belly

Other symptoms that can happen with kidney pain

The symptoms of your kidney pain depend on its cause. With kidney pain you may also have:

Causes of Kidney Pain

Kidney pain has many possible causes. These organs are connected to others like your bladder and ureters, where you store and get rid of urine.

Kidney stones. Intense, sudden, stabbing pain may be a kidney stone. These are mineral deposits that can grow large enough to block a ureter, a tube that connects your kidney and bladder. If that happens, you'll feel sharp pain or cramps in your back or side. It can also spread out to your groin. As you try to pee out the stone, you might feel waves of pain.

Kidney infection. Also called pyelonephritis, this infection could cause discomfort in one or both kidneys. You may feel pain in your back, in your side or both sides under your ribs, or in your groin. You'll also have a fever. Urinary tract infections also cause discomfort in this organ.

Kidney swelling. This condition, called hydronephrosis, can happen if your kidneys are blocked. Your urine can't drain the way it should and builds up in your kidneys. This can happen in one or both kidneys and sometimes it causes pain.

Kidney cysts. You may not feel a simple kidney cyst until it grows larger. Once it gets big, you might feel a dull pain in your side or back, or feel pain in the upper part of your belly.

Polycystic kidney disease. This genetic disease causes many cysts to grow in your kidneys. They may cause you to feel a pain in your back or side.

Kidney cancer. Tumors in your kidney may not cause any discomfort early on. As the cancer gets worse, you may notice pain in your side, back, or belly that doesn't come and go or get less intense.

Benign kidney tumor or mass. A renal mass is a noncancerous tumor or growth. It feels like pain in your flank, between your ribs and your hips on your side. You'll also have low back pain on one side of your body that lingers.

Renal vein thrombosis. A blood clot can form in one of the veins in your kidney. It causes severe, ongoing pain in your flank or side. You may feel spasms of pain at times too. The area around the affected kidney between your rib cage and spine could feel sore.

Kidney injury. Many contact sports or vigorous activities like football, boxing, horseback riding, or soccer could put you at risk for a kidney injury.

If this happens, the discomfort might be in either side of your belly or low back. It could range from mild to very strong, depending on how badly you're injured.

Kidney Pain vs. Back Pain

It's easy to confuse kidney pain for just back pain. How do you know the difference?

Location. It could be your kidney and not your back if you feel it higher on your back. Back problems usually affect your lower back.

Kidney pain is felt higher and deeper in your body than back pain. You may feel it in the upper half of your back, not the lower part. Unlike back discomfort, it's felt on one or both sides, usually under your rib cage.

It's often constant. It probably won't go away when you shift your body. With your back, it might lessen when you adjust your position.

Signs that it's your back

Back pain:

  • Shoots down one leg
  • Is more likely to be stabbing than dull and constant
  • Gets worse or flares up when you do certain activities, like lifting a box or bending over
  • When you rest or lie down, back pain may ease up
  • Might also be muscle aches

Other symptoms to watch for

Depending on the cause of the pain, you could have other symptoms too. If you have these signs, contact your doctor. You could have a serious kidney problem:

  • Fever
  • Body aches
  • Tiredness

Also, if you recently had a urinary tract infection (UTI), call your doctor. If you have blood in your urine, or if your pain is sudden and unbearable even without signs of blood in your pee, get medical care right away.

Kidney Pain Treatment

To treat your kidney pain, your doctor first needs to find its cause. They may use one or more tests to find out the cause of your pain. These tests include:

  • Urine tests to check your pee for blood, protein, too many white blood cells, and other signs of specific kidney problems
  • An ultrasound or CT scan to look for kidney stones or other physical problems in the kidneys and urinary tract

Once your doctor diagnoses the cause of your kidney pain, they can decide on the best treatment plan for you.

Show Sources


Cleveland Clinic: “Kidney Pain,” “Kidney Pain: Care and Treatment.” 

Mayo Clinic: “Kidney Pain,” “Kidney Stones,” “Kidney Cysts,” “Polycystic Kidney Disease,” “Back Pain,” “Hydronephrosis.”

National Institute of Diabetes and Digestive and Kidney Diseases: “Your Kidneys & How They Work.”

American Kidney Fund: “Kidney Pain.”

Urology Care Foundation: “What Are Kidney Stones?” “What Is Kidney (Renal) Infection -- Pyelonephritis?” “Kidney Cancer,” “What Is a Renal Mass and What Is a Localized Renal Tumor?”

Stanford Health Care: “Renal vein thrombosis.”

Korey Stringer Institute: “Kidney Injury.”

Keck Medicine of USC: “10 Signs Your Back Pain Could Be a Kidney Stone.”

Mount Sinai Medical Center: “Kidney Pain.”


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