When i sat down today i was surprised to find that my tail bone is quite tender. i haven't fallen. what could it be and what can i do to stop pain?

Coccydynia: Some folks just get this "coccydynia". Whether it "just happens" or is from "sitting improperly" (whatever that may be), you have a couple of options. Most famous is a cushion with a hole for you to put over your tailbone. A stool softener may help if bowel movements are especially painful. If you're not in pain all the time from it, just watch it; let your physician check on your next visit.

Uncertain of cause: Coccydynia is pain in the region of the coccyx or talibone. Most cases are associated with abnormal movement of the coccyx which may trigger a chronic inflammatory process leading to degeneration of this structure. Sometimes trauma in form of fracture of subluxation can cause pain.Treatment most often is conservative with non-steroidal anti-inflammatory drugs.A sudden onset of this pain can usuall.

See below: Sounds like you have coccydynia or 'tailbone pain'. This can occur with trauma to the tail bone, abnormally positioned coccyx, or poor sitting posture. Try using a good lumbar support to help shift your pelvis forward. This will put the pressure on your ischium. (bottom part of pelvic bone), and will shift the weight off of your coccyx (tailbone).