The area below the waist and above the buttocks is the sacroiliac joint, sacrum and coccyx. If there is discomfort or pain in these areas, it may be caused by sacroiliac arthritis or strain on the soft tissues around the sacrococcyx, and the pain or discomfort is caused by chronic inflammation. In addition, it may also be caused by diseases related to the lumbar spine, such as lumbar disc herniation, lumbar spinal stenosis or lumbar spinal slippage, which affects the surrounding soft tissues or compresses the nerve roots in the sacrococcygeal area, thus causing nerve pulling pain in this area, and some patients may also have numbness and weakness, etc. You can go to the hospital to take X-ray or lumbar spine CT or even MRI to make a clear diagnosis.