One of my mum's group friends broke her tailbone during birth! OUCH.............
She is still in pain and that was 7 months ago....
It has gotten better over time but not the same as it was.

None of us had heard of that before we met her but apparently it happens a fair bit! (Especially if you have already cracked it previously)

I will message her and see if she has any advice, she has just moved OS so bear with me wile I make contact!!