Investigation and diagnosis of coccyx pain
One of the first aims of investigation is to rule out any diseases such as cancer as the cause of the pain. This is very unlikely, but it needs to be checked. X-rays, CAT scans, MRI scans and colonoscopy may be used for this purpose.
When deciding on treatments, it is important to distinguish coccyx pain from low back pain or other sources not related to the coccyx (see What is coccydynia?). These other problems may cause discomfort when sitting, but require different treatments from coccydynia.
But the tests above don't identify the cause of the pain in most cases. It is necessary to do other tests to find the cause of the pain. Injection of local anesthetic and Dynamic (sit/stand) x-ray are usually more helpful in finding the cause. Unfortunately, many doctors are not familiar with these tests.