I injured my coccyx in March 2010, likely in a car accident although the real pain only started 3 weeks later after a long haul flight. Initially the pain was manageable but by November 2010 sitting on my sofa at home or even a short car journey was really uncomfortable.
I found the Sayer Clinic through recommendations on this website and saw Robert Griffiths at the Broadgate clinic (see Doctors and specialists in the UK, London). X-rays showed a partial dislocation. I had one internal manipulation (which was nowhere near as uncomfortable as I had feared) and following that had half a dozen sessions of acupuncture and ultrasound therapy. I now have no pain to touch on my coccyx, although I do experience some general achiness in the muscles around the sacrum after sitting for longer periods.
Providing I sit with good posture I can sit on hard surfaces and drive with no discomfort now - the sofa remains a challenge, so instead of slouching onto my coccyx I opt for sitting to one side.
I would highly recommend treatment at the Sayer clinic to anyone experiencing coccyx pain.