Soreness in the left leg and hip may be caused by physiological reasons such as overwork, or it may be caused by trauma, hip joint disease, lumbar degenerative disease and other factors. 1. Overwork: mostly seen in hip overactivity, resulting in spasm of the muscles around the hip joint and other tissues or accumulation of local metabolites, which may appear as the symptom of soreness of the left thigh and big hip. 2. Trauma: trauma leading to hip impingement, hip labral injury, fracture, muscle and other tissue diseases, can appear left leg big hip pain. 3. Hip diseases: such as femoral head necrosis, hip synovitis, osteoarthritis, joint tuberculosis, joint tumors, etc., all of which can stimulate the synovial membrane and the periarticular nerves, and cause the symptom of soreness of the left thigh and hip. 4. Lumbar degenerative diseases: lumbar disc herniation, spinal stenosis compression of the nerve root, can appear in the innervated area of the hip joint, hip, lower limbs of the soreness, numbness and other symptoms. There may be other reasons for the left leg and hip pain, so you should go to the hospital in time and give targeted treatment after clarifying the cause.