What should you know about posterior flank pain?

Pain after lifting, twisting, coughing, or prolonged sitting may reflect a strained muscle or irritation around the spine. Pain that comes in waves, spreads toward the groin, or occurs with blood in the urine can be associated with kidney stones. A kidney infection may present with pain in the flank or back alongside fever, chills, nausea, or painful and frequent urination. A urinary tract infection can cause urinary symptoms, although flank pain suggests that assessment should not be delayed. Burning, tingling, or a stripe of sensitive skin may point toward nerve irritation or shingles. The location alone cannot identify the cause.

Note when the pain began, whether movement changes it, and whether it travels. Record fever, urinary changes, vomiting, rash, bowel changes, or numbness. Gentle movement and avoiding the activity that triggered the pain may help when it seems muscular. Drink normally unless a clinician has told you to restrict fluids, and do not take leftover antibiotics. Arrange a clinical assessment if pain persists, recurs, is severe, or comes with urinary or general symptoms.

Seek urgent medical help for severe or rapidly worsening pain, fever with flank pain, repeated vomiting, fainting, confusion, or blood in the urine. Get immediate help for new leg weakness, numbness around the groin, or loss of bladder or bowel control. These symptoms can signal a serious infection, obstruction, nerve problem, or another condition needing prompt treatment.

Could the pattern suggest a muscle, nerve, kidney, or urinary cause? Do I need a urine test or imaging? Which pain medicines are suitable with my health conditions and current medicines? What changes should prompt urgent review?