Pain in the back of the thighs may be due to cold stimulation, muscle damage, hypocalcemia, which can be dealt with through warmth, physical therapy and calcium supplementation respectively. 1. Cold stimulation: When the legs are stimulated by cold, such as blowing the air conditioner at too low a temperature, it will slow down the blood circulation in the legs and reduce the supply of oxygen, which will lead to the accumulation of lactic acid and stimulate the muscles to trigger pain, which can be relieved by increasing the clothing to keep the affected area warm. 2. Muscle injury: trauma, excessive exercise, etc. can lead to muscle strain at the back of the legs, causing sudden pain at the back of the thighs, which can be relieved by short-wave therapy or pulse therapy. 3. Hypocalcemia: Calcium ion deficiency will lead to dysfunction of thigh muscle contraction, which may lead to cramps and sudden pain on the back side of the thigh, which can be treated by oral calcium carbonate tablets to supplement calcium. In addition, direct violence or indirect violence can also cause traumatic pain, such as the symptoms of pain in the back of the thigh, and the pain continues to be unrelieved, it is necessary to go to the regular hospital in a timely manner to clarify the cause of the doctor according to the situation of the individualized treatment plan, in order to avoid delaying the condition.