Left inner thigh pain may be caused by ischemic necrosis of the femoral head, muscle strain, strenuous exercise and other reasons. 1. Ischemic necrosis of the femoral head: it may be a disease caused by fracture of the femoral neck, excessive alcohol consumption, decompression sickness, etc., which destroys the blood supply of the femoral head. Patients may experience pain mainly in the groin, buttocks and thigh area as the disease progresses, i.e., pain in the inner left thigh. 2. Muscle strain: when the muscles of the inner left thigh are sharply contracted or overstretched during exercise leading to injury, pain and localized swelling at the injured area may occur. 3. Strenuous exercise: It may be caused by prolonged labor, running, excessive stretching of the thigh muscles, etc. Lactic acid accumulation can occur in the inner left thigh, resulting in pain. It is recommended that patients with left inner thigh pain go to the hospital in time, do relevant examinations to clarify the cause of the disease, and then follow the doctor’s instructions for treatment, so as to avoid delaying the condition.