There are many reasons for sleeping up with back pain, such as physiological factors, catching a cold, lumbar dorsal myofasciitis, ankylosing spondylitis and so on. 1. Physiological factors: excessive daytime exercise or fatigue, sleep at night in an incorrect position, etc., will cause the phenomenon of back pain in bed, which is a normal phenomenon, and will be relieved after sufficient rest. 2. Cold: Sleeping without a good blanket, cool and humid environment, etc., may lead to the lumbar muscles cold, muscle spasm, thus appearing to sleep up back pain. 3. Lumbar dorsal myofasciitis: Lumbar dorsal myofasciitis can also cause low back pain while sleeping, which is an aseptic inflammatory disease and may be related to chronic strain. 4. Ankylosing spondylitis: Ankylosing spondylitis can also cause back pain while sleeping, accompanied by sacroiliac joint pain and spinal pain. There are many causes of back pain in bed, if accompanied by discomfort or pain is obvious, it is recommended that patients go to the hospital in time to improve the examination, under the guidance of the doctor to give standardized treatment.