help?

I have been with my boyfriend 2 years and we have sex regularly but as soon as we don’t have sex for 4 days, i go back really tight and sex becomes very very painful again (like when i lost my virginity). Sometimes sex does hurt even if we haven’t had that much of a gap. We’ve tried lube and doing ridicules amounts of foreplay... does anyone else have the same issue or know anyways to sort this, as it just making me feel bad at the minute...