After the occurrence of thigh acidity, the causes of the occurrence of: a. seen in the cold, fever, after the occurrence of the cold fever, the thigh area muscle creatine secretion too much, resulting in muscle spasm, leading to thigh acidity. Second, seen in the thigh area of muscle strain, mostly due to excessive force activities in the thigh area, resulting in muscle spasm, edema, resulting in the thigh area soreness. Third, see in the cold, long time in the cold, damp environment, resulting in muscle spasm, contraction of the thigh area, leading to the symptoms of thigh soreness. Fourth, seen in the thigh area of the nerve compression, such as lumbar disc herniation, lumbar spinal stenosis, lumbar spine slippage, pear-shaped muscle syndrome in the hip, or sciatic nerve injury, sciatic neuritis, resulting in the loss of innervation of the muscles in the thigh area, causing spasm, sore symptoms.