Pain under the buttocks and lateral thighs can be caused by the following reasons: First, myofasciitis of the buttocks and the back of the thighs, these two diseases can lead to pain under the buttocks and lateral thighs at the fascia, often soreness, pain is more obvious in the cold, when the pain is more pronounced when you are tired, it is necessary to early checkups and inspections, to exclude other diseases to diagnose. Second, lumbar spine disease, when the lumbar intervertebral disc compression of the nerves, can also lead to pain and discomfort under the buttocks, thighs, this time to check the lumbar intervertebral disc CT, MRI for early diagnosis and treatment. Thirdly, hip impingement syndrome, when the small roughness of the hip joint and the sciatic bone impingement, there can be pain under the buttocks, the outer thighs, and can be radiated to the knee, this time, we need to check the MRI of the hip joint, X-ray film for diagnosis and treatment.