Soreness in the left buttock may be related to physiological factors, or it may be caused by trauma, lumbar disc herniation, gluteal myofasciitis, pyriformis syndrome and other factors. 1. Physiological factors: such as maintaining a sitting position for a long time, resulting in prolonged stress stimulation of the gluteal fascia and muscles, which may cause left buttock soreness. 2. Trauma: Trauma to the left buttock due to accidental fall or bumping may cause left buttock pain, which may also be accompanied by localized bruising, redness and swelling. 3. Herniated lumbar intervertebral disc: The herniated intervertebral disc can easily lead to local nerve root compression, which may cause left buttock pain, and may be accompanied by radiating pain in the leg, leg numbness and other symptoms. 4. Gluteal myofasciitis: prolonged exposure to cold or overexertion causes aseptic inflammation of the gluteal muscles and fascia. It can lead to spasm of the gluteal myofascia, which may cause pain in the left buttock. 5. Piriformis syndrome: the disease can lead to edema and adhesion of the patient’s piriformis muscle, forming an irritation to the sciatic nerve passing through the piriformis muscle, inducing sciatic nerve edema, which may cause left buttock pain. Left side buttock pain, after excluding physiological factors, should go to the regular hospital as soon as possible, through the improvement of the relevant examination, diagnose the cause, under the guidance of the doctor standardized treatment.