Painful sex

So I had a baby a year and a half ago & I don’t know if that has to do with anything but when my boyfriend & I do doggy style it hurts!! It hurts so bad that I can’t continue. I don’t know why? I recently took out my IUD because I thought it was that but it still hurts. It hurts around my pelvic area. I haven’t told my doctor just because I’m a little embarrassed but do any of you know why that happens? It’s literally every single time & only doggy style position. & no it’s not because he has a big one, I’ve had bigger before & it never hurt like that.. it really sucks, that’s his favorite position & we can’t do it. Any advice on what to do? How to make it less painful?