Signs that your chronic back pain is actually an issue with your kidneys, according to doctors

• Back pain is common after an injury or muscle strain, during pregnancy, or if you have poor posture.
• Pain that feels deep in your back and happens in waves may actually come from your kidneys.

If you feel pain somewhere around your spine, your first thought might be that you've strained a muscle or injured your back. But your back may have nothing to do with it — the pain could be coming from one of your kidneys.

Because your kidneys are very close to your back, it's possible to mistake kidney pain for back pain — but these two types of pain have different causes and treatments.

Kidney pain is typically caused by inflammation or diseases that affect your kidneys. Back pain, on the other hand, is typically caused by damage to the tissues in your back. Learning to tell them apart can make it easier to get the right treatment and relieve your pain.

Read on to learn the differences between kidney pain and back pain, possible causes of each, and what to do next.

What does back pain feel like?

Back pain affects the area from your shoulders down to your buttocks. It can range from a sudden, sharp shooting or stabbing pain to a dull, constant ache.

It may also involve other symptoms, such as:

• Muscle spasms, or contractions and tightening of your back muscles
• Swelling or warmth in the painful areas of your back
• Weakness in one or both legs

Also, you may notice that your back pain:

• Temporarily improves when you rest, apply heat or ice, or take pain-relieving medication such as acetaminophen or ibuprofen.
• Feels less intense or goes away when you bend, twist, stand up, or otherwise change your position — though in some cases, these movements may also make your pain worse.

• Feels worse in the morning but improves as you get up and move around, according to Dr. Piruz Motamedinia, associate professor of urology and endourology at Yale University.

What does kidney pain feel like?

Kidney pain can feel aching, stabbing, excruciating, or cramping, and it typically comes and goes in waves.

Since your kidneys are below your rib cage — about elbow level, when your hands rest at your sides — you'll most likely feel kidney pain in that area.

You may also feel pain in your abdomen or groin, including the tip of your penis, testicle on the same side, or your vagina or labia, Motamedinia says.

Note: With back pain, you may feel as if you can reach and touch the painful spot. But kidney pain typically feels deeper and hard to reach.

Kidney pain usually involves other symptoms, too, says Dr. Rena D. Malik, Director of Female Pelvic Medicine & Reconstructive Surgery at the University of Maryland School of Medicine. These symptoms may include:

• Fever and chills
• Vomiting and nausea
• Painful urination
• Cloudy or dark urine
• Urine that contains stones or particles
• A recent urinary tract infection (UTI)

Kidney pain generally won't improve until you identify and treat the root cause.

What causes back pain?

Common causes of back pain include:

• Muscle or ligament strain: You can strain muscle or ligaments in your back during activities like overstretching and lifting weights. Strained muscles are responsible for most cases of back pain.
• Poor posture: Poor posture, which might mean sitting without proper support or in a hunched-over position, can place pressure on your back and cause mid or low back pain.

• Muscle tension: This condition may happen due to stress, bed rest, or overusing your muscles.
• Infections: Any infections of the bones and tissues of the spine and ribs such as osteomyelitis, epidural abscesses, and disc space infections can cause back pain.
• Injuries: Though it might go without saying, your back will probably also hurt after a fall or any other injury.

• Osteoporosis: If you have this condition, your bones begin to lose their density and become weak. Back pain is a common symptom of this condition, and you may also feel pain in other parts of your body, such as your knees and hips.

• Cancer of the spine: With this rare condition, the cells in the spine multiply abnormally, compressing and damaging surrounding tissues. Spine cancer can also be caused by cancer cells from another organ spreading to your spine. Other symptoms may include weight loss and swelling in your back.

• Herniated disc: Also known as slipped disc, this painful condition happens when parts of your spine slip out of place. It can trigger a sharp burning pain anywhere along your spine.

• Sciatica: Sciatica is an irritation of your sciatic nerve (which runs from your lower back to the feet). Sciatica may also involve leg pain and tingling or numbness in your back and legs.

• Ankylosing spondylitis: This condition causes chronic inflammation of the spine and other areas of the body can also cause stiffness in your spine, ribs, hips, and knees. Other symptoms include fatigue, difficulty taking deep breaths, and vision problems.

• Spinal stenosis: With this condition, your spinal canal becomes narrower and compresses your nerves. You may also experience numbness, tingling, or weakness in your legs and arms.

• Pregnancy: The extra forward-facing weight you carry during pregnancy can strain your back, but this back pain will usually stop when the pregnancy ends.

What causes kidney pain?

Your kidneys filter waste from your body, make urine, and produce hormones that regulate red blood cell formation and bone function.

Pain in your kidneys is usually caused by diseases of the kidney and other parts of the urinary system. Some causes of kidney pain include:

• Kidney stones: Kidney stones form when minerals accumulate in your kidneys. You may pass smaller kidney stones while urinating, but large stones can block your urinary tract and cause pain that feels burning, stabbing, sharp, or dull.

• Urinary retention: If you have difficulty urinating, the trapped fluid in your bladder can stretch it beyond its usual size, causing pain that may range from mild to severe. You may also notice swelling in your lower abdomen.

• Vesicoureteral reflux: With this rare condition, your bladder doesn't empty properly because the urine goes back into one or both kidneys through your ureters — the tubes that carry urine to your bladder. This condition can happen when your kidneys or ureters don't function as they should, and it's most common in children. Other symptoms include an urgent need to pee, bedwetting, and frequent UTIs.

• Injury: Damage to your kidney from an accident, fall, stabbing, gunshot, or other injuries can also cause pain.
• Kidney cancer: If you have cancer in one or both kidneys, you may have other symptoms along with kidney pain, such as fatigue, unexplained weight loss, and blood in your urine.
• Kidney infections: These occur when bacteria or viruses enter your kidney. Other symptoms include fever, chills, and pain while peeing.

• Ureteral stricture: This condition happens when the ureter narrows due to things like inflammation, radiation, damage during surgery, pressure from tumors, or damage from large kidney stones. Other symptoms of this condition include fever, nausea, and vomiting.
• Polycystic kidney disease: This genetic disorder causes cysts in your kidney, liver, pancreas, and other organs. You may also experience headaches, swelling in your abdomen, high blood pressure, and blood in your urine.

When to get medical attention

Back pain may go away on its own, but you can also get relief by:

• Applying warm or cold compresses
• Doing gentle stretching or massage
• Correcting your posture by standing at your desk, using a back rest, or using an ergonomic chair where possible
• Taking over-the-counter (OTC) pain relievers such as ibuprofen or acetaminophen
• Trying aerobic exercise such as rowing, cycling, or using an elliptical machine (but only when a doctor has confirmed that it's safe for you)

Important: Back pain that doesn't improve with rest and pain relief strategies may suggest a serious health concern. So, you'll want to get medical attention if you continue to experience pain.

Home remedies usually won't do much to ease kidney pain, since they can't address the underlying cause. If you think your pain comes from your kidneys, you'll want to make an appointment with a doctor right away.

It's always a good idea to seek medical attention if any pain you experience:

• Is severe
• Happens with other symptoms
• Lingers or comes and goes over more than a week

Your doctor may ask questions about the pain and your health in general, such as:

• Your usual exercise routines
• The kind of work you do
• Any treatments you've tried
• Other symptoms you've noticed
• What relieves your pain or makes it worse
• Recent injuries, medical procedures, or surgeries
• Any effects on your daily life — for instance, if your pain causes you to miss school or work, or makes walking and other movements difficult

They may also examine your back and abdomen and recommend tests to help make the right diagnosis, such as:

• Urinalysis: This test helps your doctor check for blood, particles, or signs of infection in your urine.
• Complete blood count (CBC): This test shows your blood cell count and concentration and helps your doctor spot possible cancers, inflammation, and infections.
• MRI or CT scans: Imaging tests — like magnetic resonance imaging (MRI), computed tomogram (CT), an ultrasound, or bone scan — can help your doctors examine your bones, muscles, kidneys, and other organs for any signs of a problem.
• Electromyography: Also called nerve conduction tests, these tests help your doctor check whether your nerves are working as they should.
• Erythrocyte sedimentation rate (ESR) and c-reactive protein tests: These blood tests can help identify ongoing inflammation anywhere in your body.

Insider's takeaway

Back pain and kidney pain have distinct causes and come from different parts of the body, but you may not always find it easy to tell them apart.

If you experience pain that won't go away, involves other symptoms, or seems to come from deeper in your back, you'll want to connect with your doctor as soon as possible.

A doctor can recommend tests to help pinpoint whether the pain comes from your back or your kidneys. They can also recommend the best treatment to help you not only get relief, but also lower your risk of long-term complications.