The main causes of lumbar pain in the morning are the following: 1. incorrect posture of sleeping at night, improper softness of the bed at night, or the stimulation of wind and cold due to air conditioning or fan blowing at night, which leads to spasm of the lumbar muscles and affects the blood circulation of the lumbar region, thus inducing the phenomenon of lumbar pain after waking up in the morning. 2. The pain in the lumbar region after waking up in the morning can also be caused by diseases of the lumbar spine, such as herniated discs, stenosis of the spinal canal and osteophytes of the lumbar spine.