Why suddenly sex hurts?

Hi All,

Setelah galau diputusin mantan tahun 2023, akhirnya aku menjalin hubungan baru akhir tahun lalu. We decided to have sex for the first time as a couple and suddenly I feel like sex hurts a lot more with him. It’s not the first time I have sex and I have never do any one night stand with anyone ever before meeting my current partner. For information, I am currently on birth control and got no history of STD and he’s also clean. Sex with my ex was using condom instead of birth control pill, also (sorry) his size was smaller than my current partner. The pain is like burning/stinging in the outer (sorry) vagina and basically I cannot continue because it hurts a lot, even lube cannot help. Is it possible that birth control may cause this issue? I read hormonal change may contribute and vaginal dryness as side effect is also possible.

Thank you appreciate for any feedback or similar issue :(