The back stiffness and soreness in the morning may be related to the following reasons: 1, over fatigue, many patients have done intense activities in the first day, resulting in a large amount of lactic acid deposition inside the muscles, which will lead to a stiff and sore back after rest. 2, the bed is too soft, many patients are used to sleeping on a relatively soft mattress, and a soft mattress will lead to the patient in the process of sleep, the spine is in an abnormal curvature. 3, bad sleeping posture, there are many patients in the sleep, will maintain some bad sleeping posture, so that a muscle group continued to produce spasm, after waking up will feel this symptom. 4, rheumatic diseases, such as ankylosing spondylitis or rheumatism, rheumatoid arthritis Patients, after waking up in the morning may also have similar symptoms.