Advice please

So im 21, I’ve been married for almost four years now and we have a son together. Before my husband I only had two other sexual partners and they were both smaller than my husband ( like a WHOLE lot smaller). Since we’ve been together sex is enjoyable but I never moan or have an orgasam just from penetration, it actually feels uncomfortable or like it’s “too much “. I’m not very confident in certain positions (mostly being on top). What can I do to make sex more enjoyable for myself and how can I be more confident while riding? Tips please..