There have been numerous posts here on tailbone pain. Doing a search and reading the lot would likely be very useful to you. Here's what I replied to one in April of last year:
A couple of years ago I developed significant tailbone pain (it was worst when getting off a chair - I would make quite a face getting off the stationary bicycle). I never really did much about it, and it very slowly receded and is now essentially gone. OTOH I've been on antibiotics the whole time, more or less, so who knows?