Could it be because you haven't done it lately? That would be my guess, or maybe check yourself to see if you have some bruise or something that might cause irritation.
Also you know you have more blood flow down there. It tends to get um plumper so if your um tight it might be painful that way too. Lol can't really describe that any better
It just feels painful. We usually do missionary , but he wants to do doggy but since they can go Dewey that won't help.
How so did it hurt? Your cervix gets lower closer to the end and depending on the position you may feel him hitting it and it can be painful. Try a different position. I've noticed doggy style can be extremely painful bc the can go deeper. Missionary obviously is uncomfortable bc your belly is so big and ask that weight is laying in your bladder. Try laying on your side and him behind you. If that doesn't help idk what to tell you.