Currently dealing with this issue and found this forum. Have first gone to a chiropractor which was a first as I am in the women's health care field myself, but did not get any help with the tailbone pain. Primary doctor had me get a regular lower back x-ray which just showed a minor displacement that she said was no worry.
With some help from my coworkers, I got directed to the departments pelvic floor physical therapist. Also have been told to get a new bike seat. Last year I had a proper bike fit. Last year got a new saddle which took care of the labial lesions the old one caused. Non riders don't understand that it is very difficult to just buy more and more saddles to try out without guidance as to what might work.

PT and I are thinking of an injection nest as the therapy doesn't seem to helping yet. Funny, it doesn't hurt while on the bike, well the lower back does but not the tailbone itself.

I'll keep searching as I don't intend on not riding.