The pain in the lower back occurs when the patient is lying flat on his back, but not when he is lying on his side. This condition is basically triggered by some problem in the lower back. The most common is that the muscles of the lumbar region are strained, and at night, when the patient chooses to lie flat when the lumbar region is locally compressed, and the point of stress is particularly obvious, so the pain in the lumbar region occurs, while the patient, if he chooses to sleep on his side, will be due to the change of body position as well as the muscles, ligaments are stretched and changed, and the pain is relieved. In this case, it is best to recommend that the patient timely to the hospital, specifically to find out which cause of pain, and then give targeted treatment, such as localization can be combined with hot compresses, massage, but also can be applied to some non-steroidal drugs or blood-boosting drugs to carry out the auxiliary treatment.