Lower-left flank pain: possible causes and next steps

The lower flank overlaps with the side of the abdomen and the upper pelvis. Kidney stones may cause intense pain that comes and goes and travels downward. Kidney infection may present with flank pain, fever, chills, nausea, or discomfort when urinating. A urinary tract infection may cause burning, urgency, and frequent urination. Constipation or bowel inflammation can cause lower-sided abdominal pain and changes in bowel habits. Strained abdominal or back muscles tend to hurt with movement or touch. In people with ovaries, cycle-related pain or an ovarian problem may also be felt low on one side.

Track the pain beside meals, bowel movements, urination, exercise, and your menstrual cycle. Keep activity gentle and use only medicines that are safe for you and taken according to the label or a clinician's advice. Arrange a medical review when pain lasts, keeps returning, or is accompanied by urinary, bowel, or pelvic changes. Tell the clinician if pregnancy is possible, because this affects the urgency and choice of tests.

Seek urgent care if the pain is severe, sudden, worsening, or accompanied by fever, repeated vomiting, fainting, confusion, a rigid or very tender abdomen, inability to pass urine, or blood in urine or stool. One-sided pain with vaginal bleeding, dizziness, or possible pregnancy needs immediate assessment.

Could the pain be coming from my kidney, bowel, muscles, or pelvis? Do my symptoms call for urine, blood, pregnancy, or imaging tests? Which warning signs should make me seek help sooner?