Soreness in the right leg while sleeping may be related to lumbar spine lesions, leg compression, cold, and high activity level. 1. Lumbar spine lesions: lumbar disc herniation, lumbar spinal stenosis will compress the spinal cord and the right side of the nerve root, sleep lying down when the nerve root is stimulated will appear right leg pain and numbness and other symptoms. 2. Leg pressure: the bed board is hard, sleep at night to the right side of the habit of lying down, the right leg is compressed, the right leg will appear the symptoms of pain, generally lying down or the left side of the lying position will be relieved. 3. Cold: blowing air-conditioning fan in hot weather in summer, the right leg will also appear after the cold soreness. 4. High activity level: excessive activity during the day will cause muscle fatigue in the right leg, and right leg or both legs will be sore at night when you sleep. If the soreness of the right leg occurs continuously during sleep, it is recommended that the patient go to the hospital for medical examination.