If there is frequent soreness above the tailbone, it is usually seen in the sacroiliac joint. If there is significant soreness in the sacroiliac joint, first rule out whether it is caused by muscle strain. Soreness caused by muscle strain is usually manifested as a distinct soreness next to the sacroiliac joint. In addition, this soreness is often obvious after waking up in the morning, and some patients often have a significant morning stiffness after waking up, which disappears after light activity, which is mostly indicative of a muscle strain. For this kind of muscle strain must pay attention to the local warmth, reduce bending and heavy lifting, can be appropriate heat compress, choose massage can be effective treatment. It can also be seen in the early reaction of sacroiliac joint inflammation, sacroiliac joint inflammation is often directly related to chronic strain, local ligamentous hyperplasia, calcification and bone degeneration, which will often show significant pain in the sacroiliac joint in the early stage, this sacroiliac joint inflammation can often be diagnosed by doing sacroiliac joint CT. It is also necessary to rule out early reactions to ankylosing spondylitis, which are often accompanied by significant soreness in the sacroiliac joint and often by morning stiffness and limited movement of the entire spine.