There are many reasons for hamstring pain in the leg fossa, most of which are caused by physiological factors such as prolonged standing and exertion, and may also be related to pathological factors such as fasciitis and popliteal cyst. 1. Physiological factors: when the human body is standing for a long time or sports exertion, the muscles are in a state of stretching or tension for a long time, resulting in muscle spasm, which causes popliteal tendon pain. 2. Fasciitis: mostly seen in people who frequently exercise the lower limbs or heavy manual laborers, which can cause aseptic inflammation in the soft tissues of the popliteal fossa, and the inflammation stimulation can lead to hamstring pain in the popliteal fossa. 3. Popliteal cysts: when the popliteal fossa appears cysts, it can compress the peripheral nerves and muscles, and popliteal pain occurs. There may also be other causes of hamstring pain, such as lumbar disc herniation, low blood calcium, etc. It is recommended to consult a doctor in time, complete the relevant examinations, and carry out targeted treatment after clarifying the cause of the disease.