Lying down with back pain may be caused by osteoporosis, severe lumbar muscle strain, lumbar disc herniation and so on. 1. Osteoporosis: when suffering from severe osteoporosis, due to the decline in the strength of the bone, the bone is more fragile, lying down easily lead to lumbar vertebrae deformation, stimulation of the surrounding nerve tissue, which leads to lying down the symptoms of lumbar pain. 2. Severe lumbar muscle strain: If the lumbar region is loaded for a long time, the lumbar muscles are overly stretched to form lumbar muscle strain, and when the lumbar muscle strain is more serious, due to the change of position when lying down, it will lead to lumbar soreness and pain symptoms. 3. Lumbar disc herniation: when the lumbar disc herniation patients lie down, due to the lumbar vertebrae part of the suspension, the lumbar muscles are in a state of tension, thus stimulating the lumbar disc herniation part, aggravating the compression of the lumbar spinal nerves caused by the lumbar soreness symptoms. Lying back pain may also be caused by fasciitis, lumbar tumors, lumbar spine infection, etc. It is recommended to go to the hospital in time for the relevant examination to clarify the causes of lying back pain, and then follow the doctor’s instructions for treatment.