Back pain and sex tips

Alright ladies, me and my boyfriend have had sex about 4 times each time better than the last lol. The last time was by far the best. No pain and we tried doggy styles and later missionary which is usually what we do. Has anyone experienced back pain after sex? I’m gonna assume it’s normal bc I’m not used to it yet. Just curious if anyone else feels the same. Also I would love to hear any tips you could offer me since I’m new to this whole thing. Position ideas things that we can try to get me to orgasm would be appropriated. He hasn’t made me do it yet and he feels discouraged and disappointed after. So any tips or tricks would be appropriated. ☺️ thanks xx