Hello and Welcome to HCM,
Thanks for writing to us.
From description it seems you might having coccydynia
(pain and inflammation over coccyx
I suggest you to sit on soft cushion. avoid sitting in same position for prolonged hours.
Do sitz bath(take warm water in tub and sit to do fomatation). You can take antiinflammatory drug like motrin
to reduce pain and inflammation.
Hope this helps you.
Wishing you good health...
Dr Saurabh Gupta.