There are two most common reasons for pain in the left hip that occurs even when walking: the first one is acute injury and chronic strain on the muscles of the left hip. Strains, contusions and lacerations of the hip muscles caused by acute violence during daily exercise can produce pain due to acute injury. Or chronic cumulative damage to the hip muscles due to long-term high-load activities or poor posture of the lower extremities may also produce this symptom. The second one is seen in lumbar spine diseases, which cause compression of the nerve roots of the lower limbs, resulting in pain in the buttocks, which will be aggravated during activities, and in severe cases the pain will radiate to the distal end of the limbs, producing abnormal sensation of muscle strength in the lower limbs, thus obviously affecting the function of the lower limbs.