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Published on: 2/24/2026

Is It Just Back Pain? Why Your Kidney Is Aching & Medical Next Steps

Kidney pain typically feels like a deep, one-sided ache in the upper back or flank that does not improve with position changes and is often paired with urinary symptoms or fever, pointing to causes like a kidney infection or kidney stones rather than simple muscle strain.

Seek urgent care for fever with flank pain, severe or worsening pain, vomiting, blood in urine, confusion, or signs of dehydration; clinicians confirm the cause with urine, blood, and imaging tests and treat infections promptly with antibiotics. There are several factors to consider, so see the complete next steps and important details below.

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Explanation

Is It Just Back Pain? Why Your Kidney Is Aching & Medical Next Steps

Back pain is common. Most of the time, it's caused by muscle strain, poor posture, or lifting something heavy. But sometimes what feels like back pain is actually coming from your kidneys. Knowing the difference matters—especially if the cause is a kidney infection, which can become serious without treatment.

Let's break down how to tell the difference, what symptoms to watch for, and what to do next.


Where Is Kidney Pain Felt?

Your kidneys sit just below your rib cage, one on each side of your spine. Pain from the kidneys is usually felt:

  • In the upper back or flank area
  • On one side (though it can affect both)
  • Deeper than muscle pain
  • Sometimes spreading to the lower abdomen or groin

Unlike common back pain, kidney pain often doesn't improve when you change position or stretch.


Back Pain vs. Kidney Pain: Key Differences

Here's how they typically compare:

Muscle-Related Back Pain

  • Often triggered by movement or lifting
  • Gets worse with bending or twisting
  • Improves with rest
  • May feel tender when you press on the area
  • No urinary symptoms

Kidney-Related Pain

  • Felt deep in the flank area
  • May be constant or severe
  • Not clearly tied to movement
  • Often accompanied by urinary symptoms
  • May come with fever or nausea

If you're unsure, pay attention to other symptoms. That's often where the biggest clues are.


Could It Be a Kidney Infection?

A kidney infection (also called pyelonephritis) is a type of urinary tract infection (UTI) that spreads to the kidneys. It's more serious than a simple bladder infection and requires prompt medical care.

Common Symptoms of a Kidney Infection

  • Pain in the upper back or side
  • Fever (often above 101°F / 38.5°C)
  • Chills or shaking
  • Nausea and vomiting
  • Burning or pain with urination
  • Frequent urge to urinate
  • Cloudy, dark, or foul-smelling urine
  • Blood in the urine

A kidney infection can develop quickly. Some people feel fine one day and significantly ill the next.

Who Is at Higher Risk?

  • Women (especially those with frequent UTIs)
  • Pregnant individuals
  • People with kidney stones
  • Individuals with diabetes
  • Anyone with a weakened immune system
  • People with urinary tract blockages

Without treatment, a kidney infection can spread to the bloodstream (sepsis), which is life-threatening. This is why early evaluation is important.


What About Kidney Stones?

Kidney stones are another common cause of kidney-area pain. They form when minerals in the urine crystallize and clump together.

Symptoms of Kidney Stones

  • Sudden, severe pain in the side or back
  • Pain that moves toward the lower abdomen or groin
  • Waves of intense pain
  • Blood in urine
  • Nausea and vomiting
  • Frequent urination

The pain from kidney stones is often described as one of the most intense types of pain a person can experience. Unlike a kidney infection, stones don't always cause fever—unless they lead to infection.

If you're experiencing symptoms like severe flank pain, blood in your urine, or waves of intense discomfort, it may help to check your symptoms using a free AI-powered tool designed specifically for Nephrolithiasis (Kidney Stones) to better understand what you're dealing with before your doctor visit.


Other Possible Causes of Kidney Area Pain

While kidney infection and kidney stones are common causes, other conditions can cause pain in this area:

  • Bladder infections (UTIs)
  • Spinal problems (herniated discs, arthritis)
  • Muscle strain
  • Shingles (before rash appears)
  • Abdominal conditions (like appendicitis on the right side)

Because symptoms can overlap, medical evaluation is often needed to confirm the cause.


When Should You Seek Immediate Medical Care?

Seek urgent medical attention if you have:

  • Fever with back or side pain
  • Severe or worsening pain
  • Confusion or extreme fatigue
  • Persistent vomiting
  • Signs of dehydration
  • Blood in your urine
  • Rapid heart rate
  • Low blood pressure symptoms (dizziness, fainting)

These may signal a kidney infection or a complication that needs fast treatment.


How Doctors Diagnose Kidney Problems

If you see a healthcare provider, they may:

1. Ask About Your Symptoms

  • Location and severity of pain
  • Urinary changes
  • Fever or chills
  • Recent infections

2. Perform a Physical Exam

  • Tapping gently over your kidney area (this can be painful in kidney infection)
  • Checking temperature and vital signs

3. Order Tests

  • Urinalysis (to look for bacteria, blood, white blood cells)
  • Urine culture (to identify bacteria in kidney infection)
  • Blood tests (to check kidney function and infection markers)
  • Imaging tests (ultrasound or CT scan) if stones or blockages are suspected

Prompt testing is especially important if a kidney infection is suspected.


How Is a Kidney Infection Treated?

A confirmed kidney infection is treated with antibiotics.

Mild to Moderate Cases

  • Oral antibiotics for 7–14 days
  • Increased fluid intake
  • Pain management
  • Close follow-up

Severe Cases

  • Hospitalization
  • IV antibiotics
  • Fluids through an IV
  • Monitoring for complications

Most people recover fully with timely treatment. The key is not delaying care.


What Happens If a Kidney Infection Is Ignored?

It's important not to "wait it out" if you suspect a kidney infection.

Without treatment, it can lead to:

  • Kidney damage
  • Abscess formation
  • Sepsis (bloodstream infection)
  • Organ failure in severe cases

These complications are uncommon when treatment starts early—but they can happen if symptoms are ignored.

This isn't meant to alarm you, but to stress the importance of timely medical evaluation.


How to Reduce Your Risk

You can lower your chances of kidney infection and kidney stones by:

  • Drinking plenty of water
  • Not holding in urine for long periods
  • Urinating after sexual activity
  • Wiping front to back (for women)
  • Managing diabetes carefully
  • Treating bladder infections promptly
  • Limiting excessive salt intake (to reduce stone risk)

Small habits make a big difference over time.


The Bottom Line

Not all back pain is "just back pain." If you have:

  • Deep flank pain
  • Fever
  • Urinary symptoms
  • Severe or unusual pain

It may be more than a muscle strain.

A kidney infection is treatable—but it requires medical care. Kidney stones can also cause intense pain and sometimes lead to infection. Paying attention to your body and acting early helps prevent complications.

If your symptoms are severe, worsening, or accompanied by fever, vomiting, or confusion, seek urgent medical attention immediately.

Even if your symptoms are mild, it's wise to speak to a doctor about any persistent kidney-area pain. Conditions involving the kidneys can become serious if left untreated, and early treatment leads to better outcomes.

Your body often gives clear signals when something isn't right. Listen to them—and don't hesitate to get professional guidance when needed.

(References)

  • * pubmed.ncbi.nlm.nih.gov/32098270/

  • * pubmed.ncbi.nlm.nih.gov/29549303/

  • * pubmed.ncbi.nlm.nih.gov/35008453/

  • * pubmed.ncbi.nlm.nih.gov/35848520/

  • * pubmed.ncbi.nlm.nih.gov/34185123/

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