What should you know about colicky left flank pain?

Colicky left flank pain is wave-like discomfort in the side of the back that may need assessment for a urinary or other abdominal cause. Pain can rise and ease repeatedly, sometimes spreading towards the groin. Its pattern alone cannot identify the cause.

A urinary blockage such as a kidney stone can cause severe, shifting waves of pain. A kidney infection may cause flank discomfort with fever, chills, nausea, or urinary symptoms. A bladder infection can cause burning or frequent urination without the same pain pattern. Muscle strain, bowel problems, or irritation from another abdominal structure can also feel like flank pain. The side affected, urine changes, bowel symptoms, fever, and tenderness help guide an examination. Read more about [Kidney Stones](/conditions/kidney-stones/), [Kidney Infection](/conditions/kidney-infection/), and [Urinary Tract Infection](/conditions/urinary-tract-infection/).

Note when each wave starts, where it travels, and whether movement changes it. Record fever, vomiting, urine colour, burning, frequency, or blood. Sip fluids if you can keep them down, rest, and use only pain medicine that is suitable for you and taken as directed. Do not delay assessment because pain briefly settles. A clinician may need an examination and urine testing to distinguish urinary causes from other problems. See the overview of [Flank Pain](/symptoms/flank-pain/).

Get urgent help for severe or persistent pain, fever with flank pain, repeated vomiting, faintness, confusion, inability to pass urine, visible blood in urine, or pain during pregnancy. Seek prompt care if you have one kidney, known urinary disease, or worsening symptoms.

Ask whether your symptoms suggest a stone, infection, muscle problem, or another cause; whether urine or imaging tests are needed; and which pain-relief options are appropriate.