Left flank pain under the rib

The kidney sits toward the back beneath the lower ribs, so kidney stones or kidney infection can cause flank discomfort there. A kidney stone may cause sharp, shifting pain, nausea, or blood in the urine. Kidney infection may bring fever, chills, urinary symptoms, and a persistent ache. A urinary tract infection may cause burning, urgency, or frequent urination. Rib or muscle pain may be tender to touch and worsen with movement, coughing, or a deep breath. Bowel gas or digestive irritation can also be felt beneath the left ribs. Pain location alone does not establish a diagnosis.

Consider whether the pain followed a blow, exercise, lifting, coughing, a meal, or a change in urination. Rest the affected area, avoid activities that worsen it, keep normal fluid intake unless a clinician advised restriction, and use suitable pain relief as directed. Arrange an appointment if the discomfort persists, returns, or is accompanied by urinary or digestive changes. A clinician can examine the ribs, abdomen, and back and decide whether urine testing is useful.

Seek urgent help for severe or worsening pain, fever, repeated vomiting, faintness, confusion, blood in urine or stool, inability to urinate, breathing difficulty, chest pain, or pain following a significant injury. Do not wait for another episode when these symptoms are present.

Ask whether the tenderness seems to come from a rib, muscle, kidney, bowel, or another structure, whether tests are needed, and what warning signs require urgent review. Describe breathing-related pain, meals, bowel movements, urine changes, and recent injury.