Sex help

I’ve started experiencing like a painful burning sensation when my boyfriend and I have sex. We haven’t had sex in 3 weeks cause he had to go home for a while uk rules etc.

Both of us are completely healthy in every aspect. I’ve gone longer periods of time without sex and never had an issue. We’ve tried twice now since he’s been back here and I just can’t. Doesn’t matter how wet or lubed up I am, even just the tip and I get this awful feeling and have to stop.

Anyone have any idea what it could be or anything we could do to try avoid it?

I’ve never had anything like this before and it’s so frustrating and just puts me in a foul mood.

I’d really appreciate any advice!