There are many causes of hamstring pain, and the common ones are tenosynovitis, trauma, tendonitis, and so on. 1. tendovaginitis: excessive friction between tendon and tendon sheath, tendon sheath tissue edema and aseptic inflammation, manifested as hamstring pain, localized pressure and pain, joint activity limitation. 2. Trauma: soft tissue strains such as hand muscles and ligaments caused by external forces, and severe trauma can cause hamstring rupture. Thus, hamstring pain occurs. 3. Tendonitis: it is a kind of aseptic inflammatory reaction of tendons or tissues around tendons caused by excessive activities or other reasons, which can occur in the joint parts of the hand, manifested as hamstring pain, pressure pain, motor dysfunction and inflammatory reaction. There may be other causes of hamstring pain such as carpal tunnel syndrome, etc. It is recommended to go to the hospital as soon as possible to clarify the cause and standardize the treatment.