Lower back pain while sleeping can occur for many different reasons, according to WebMD. The most common cause of lower back pain at night is disc degeneration, a condition where the shock-absorbing discs between the spine's vertebrae deteriorate with age.
Injuries to the spine can also cause lower back pain during sleep. Night time back pain may also be an indication of a disease or condition such as spinal stenosis, a narrowing of the spinal column, or scoliosis, a curvature of the spine. Certain cancers, pregnancy, kidney problems, endometriosis and arthritis can also cause pain in the lower back while sleeping.