What should you know about mild flank pain?

Flank pain is felt between the ribs and hips, often on one side. A muscle strain may hurt more when you twist, lift, cough, or press the area. Kidney stones can cause severe waves of pain that move toward the groin, while a kidney infection may cause flank pain with fever, chills, nausea, or urinary changes. A urinary tract infection can cause burning or frequent urination and may spread upward.

Pain location alone cannot distinguish these causes. Note its side, triggers, intensity, timing, and any change in urine or bowel symptoms.

Pause activities that clearly worsen the pain and use gentle movement if comfortable. Drink normally unless a clinician has advised fluid restriction; do not force large amounts of water to flush out a suspected stone. A pharmacist can advise on suitable pain relief after considering pregnancy, ulcers, kidney disease, and other medicines. Arrange a clinical review if the pain persists, recurs, or is joined by urinary symptoms.

Seek urgent help for severe or rapidly worsening pain, fever with flank pain, repeated vomiting, faintness, confusion, inability to pass urine, or visible blood in urine. Prompt assessment is also needed during pregnancy, with one working kidney, or when you feel markedly unwell. A clinician may need a urine test and examination to separate a kidney problem from muscle or other causes.

Could this be muscular, a stone, or an infection? Do I need a urine test or imaging? Which pain medicine is safe with my health history, and what change should bring me back urgently?