Week post birth, pain in bum

Hello! Just wondering if anyone had this or it's just my body being weird 
It's a week now since having my boy. It was pretty tough, bad tear and blood transfusion at the end of it! Anyway! I'm getting a super painful sharp shooting/aching pain in my bum area, inside (so not stitches) 
Hurts like gas I suppose but really violent gas! It's almost as painful as the early contractions! 
Thanks!