When you get up in the morning, your back hurts, but not after you get up, which may be caused by lumbar muscle strain, rheumatoid arthritis, ankylosing spondylitis and other reasons. 1. Lumbar muscle strain: Lumbar muscle strain is related to maintaining a labor position for a long time. It may also be due to cold, sedentary, and exertion. Chronic pain with no obvious cause is the main symptom, and lumbago is aching and painful, mostly relieved after rest. Straight leg raising test is positive. There is no nerve involvement in the lower limbs. 2. Rheumatoid arthritis: When rheumatoid arthritis involves the spine, low back pain can also occur when getting up in the morning, which will be relieved and disappear after a while of activity. Serologic tests and X-rays are needed to make a clear diagnosis. 3. Ankylosing spondylitis: It is common in young men. Ankylosing spondylitis mainly affects the sacroiliac joints and spinal joints. There may be a family history of ankylosing spondylitis. In the morning, there will be pain and morning stiffness, but the pain can be relieved or disappear after a short period of activity. 90% of the patients are HLA-B27 positive. It is recommended to go to the hospital in time for systematic diagnosis and treatment under the guidance of the physician if the symptoms of morning back pain appear.