I know exactly what you are going through! I cracked my tailbone during labour and pushing, DD was posterior so that didn't really help either (ouchies!!) and I tore 3rd degree too. It's normal for your tailbone to sometimes hurt after giving birth, all that pressure down there while pushing etc!! however you may have very well cracked it like i did mine. whereas some women just bruise theirs kwim?

TBH, mine is STILL pretty bad, 17mths later.... I have been seeing an Acupuncturist to help me with correcting it as she seems to be able to help with it..... sorry no advice just wanted to let you know that you're not alone!! I avoid sitting on hard chairs for very long otherwise it's just too painful.

(I also cracked it years prior so that didnt help!)