Hm,

Tailbone pain is always really tricky and in my experience poorly treated by physiotherapists. You certainly sound really complex and worthy of assessment.
We cannot be sure your pain is from hypermobility or not... but there appears to be no injury so it seems fair.

I suggest you do see a physio but you phone ahead and ask if they have had experience working with tailbones because it's a bit of a niche subject and you'd do well to find someone with experience in the matter.

Four your referance the muscles that attach to the coccyx are the gluteus maximus and the pelvic floor muscles. so if you wish to attempt to try to strengthen around the area you should be doing pelvic floor and glut exercises... However given your long history with hypermobility and your structured gym program you may do well to get some guidance on prescription. if the coccyx is hypermobile you don't want to tug on it with vigorous exercise and risk hurting yourself further.

cheers,
pudding

---------- Post added at 12:40 AM ---------- Previous post was at 12:37 AM ----------

OH and also as a bit of pain management... I find coccydinia cusions to not be very helpful. While working around obstetrics (which was uncomfortable for a 22 year old male at the time) I saw alot of coccyx pain and best thing i did was just talk to my boss who had experienced the same in her pregnancys. She basically said to sit on 2 pillows one under each thigh so the coccyx has no pressure on it at all. this may be helpful to allow you to sit for a length of time.

good luck