Sleeping on your back can be caused by the following reasons: 1, may be due to muscle spasm in the lumbar region, in the prone position when sleeping, the early may relax the muscles on both sides of the lumbar spine, but with the extension of time, part of the muscles on both sides of the lumbar spine will be gradually tense, and some patients sleeping on their back, habitually flexing one lower limb, it may cause The lumbar muscles produce very serious tension and spasm, after the patient wakes up there will be very obvious pain. 2, may be due to the lumbar cold, in taking a sleep on your back this way, may lead to the lumbar have insufficient clothing, or by the cool wind blowing situation, easy to make the lumbar muscles produce spasm, or make the lumbar fascia inflammation, and then lead to the patient lumbar pain. 3, may be due to the lumbar degeneration, It may be caused by the degeneration of the lumbar spine. When sleeping in a prone position or sleeping on your back while sitting, the lumbar spine is in an abnormal arc, which will lead to the intensification of the degeneration of the lumbar spine and then produce a series of lesions like osteophytes, ligamentous hypertrophy, calcification, lumbar disc herniation, etc., which will then lead to lumbago.