Back pain when waking up in the morning, but not during the day, the following common causes: First, back muscle strain: back muscle strain, the patient after the night rest, did not get a complete recovery, therefore, in the morning will appear back stiffness, pain symptoms, activity for a period of time, muscle blood circulation is completely restored, the pain symptoms of muscle strain will disappear completely. Second, ankylosing spondylitis: patients in the early stages can also be manifested as morning stiffness of the spine, back pain, pain will be relieved after getting up and moving. In the early stages, the pain is not obvious during daytime activities, and as the disease progresses, severe pain and spinal deformity can occur even during daytime activities. Therefore, if you wake up in the morning with back pain but not during the day, you must be diagnosed and treated promptly so that the clinical symptoms can be controlled as soon as possible.