Painful sex after c section.. help!!

So my fiancé and i got together when i was about 5 months pregnant and sex was only painful occasionally. I assumed it was because i was pregnant ( this was my first pregnancy) I’m now 7 months postpartum and it’s still pretty painful. I’ve never experienced this before with any other partner. It’s extremely painful from behind which has always been my favorite position and was never painful with anyone else. I had an emergency c section at 35 weeks because of preeclampsia. But still experiencing some pain at times but always during sex from that position. Has anyone else experienced this? Is it normal?