Lower Back / Flank Pain

Kidney & Urinary

If this is an emergency, call 911 now. This tool is for general information, not emergency guidance. If you're having severe symptoms, don't read this — get help.

What the internet says

Kidney cancer. Aortic aneurysm. Spinal tumor. Renal artery stenosis.

What it probably actually is

Muscle strain (most common cause of lower back pain overall). Kidney stones passing through the ureter (this one actually hurts — intensely — and is very distinctive). UTI with kidney involvement (pyelonephritis). Poor posture. Constipation pressing on back structures.

🧠 The full picture

True kidney pain is felt in the flank — the area between the last rib and the hip, usually on one side. It often radiates into the lower abdomen or groin. It's distinct from muscular back pain, which is usually bilateral and mechanical (hurts more with movement).

⚠️ When to actually call your doctor

These are real red flags. If any of these apply, don't wait.

Severe one-sided flank pain coming in waves (kidney stone)
With fever and chills (kidney infection — urgent)
Blood in urine with the pain
Pain persists more than a week without explanation
Known history of kidney disease

📚 Sources

This information is based on guidance from:

NIH National Institute of DiabetesAmerican Urological AssociationNational Kidney Foundation

Always verify important health decisions with your doctor or a qualified healthcare provider.

🔗 Related symptoms

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