The symptoms of pain below the waist above the tailbone and pain when bending at the waist may be caused by lumbar muscle strain, lumbar intervertebral disc herniation, lumbar spondylolisthesis, spinal stenosis and other reasons. 1. Lumbar muscle strain: long-term bending activities or sedentary, will lead to the lumbar muscles can not get timely rest, at the same time bending the human body’s muscular tissues or elongation, will cause muscle tissue damage, pain, numbness and other uncomfortable symptoms. 2. Lumbar disc herniation: when the nucleus pulposus structure of the lumbar intervertebral disc protrudes, it will compress the cauda equina nerve, and the nucleus pulposus protrudes more obviously when bending down, and the irritation of the cauda equina nerve will be enhanced, which will cause pain above the caudal vertebrae and pain below the waist, and bending down will cause pain. 3. Lumbar spondylolisthesis: when the lumbar spondylolisthesis is slipped, it may cause infringement to the cauda equina nerve, which will show the pain in the waist and the pain above the tailbone. 4. Vertebral stenosis: when the narrowing of the vertebral canal occurs, it will compress the surrounding cauda equina nerve, which will cause sensory abnormalities in the saddle area, and pain in the tailbone and low back pain will occur when bending over. When this symptom occurs, it is recommended to go to the hospital as soon as possible for professional consultation and examination, in order to clarify the cause of the disease and target treatment.