The pain in the upper 5 centimeters of the tailbone may be caused by muscle strain, fasciitis, lumbar disc herniation, ankylosing spondylitis and other reasons. 1. Muscle strain: If you often sit for a long time or often bend over, it can cause lumbosacral muscle strain and localized pain, bed rest can reduce the pain symptoms. 2. Fasciitis: strain, trauma, cold and other factors can cause lumbosacral fascia aseptic inflammation, mainly manifested as lumbosacral pain, stiffness and activity limitation. 3. Lumbar disc herniation: Lumbar disc herniation due to various reasons may compress the nerves or cause edema of vertebral body leading to aseptic inflammation and lumbosacral soreness, which can be diagnosed by CT or MRI. 4. Ankylosing spondylitis: early manifestations of lumbosacral dull pain, pain at night, difficulty in turning over, alleviated after appropriate activities. There are many other possible causes of pain in the upper 5 centimeters of the tailbone, and if it is not alleviated by rest, it is best to consult a hospital in time to clarify the cause of the disease and treatment.