Yeah, after a long time of not having sex, things start to get all closed up. Teehee. Try lots of lube. Lots of lube...foreplay. And different positions. I swear, last night, my lover and I did it and for example: if you have chair sex [guy on bottom, girl on top] its waaaaaay tight and hurts a tiny bit. But using the same chair, if you get down on your knees in front of it and grip it, then have him push into from behind, it feels hellllaa good.
My advice short: Try different positions, after foreplay and lots of lubing up. Teehee. Good luck.