Sex and burning sensation?

well every time my fiance cums inside me it burns and i want to go to the bathroom and wash the *** out. its not out of the way unbearable but it isnt comfortable. at first i thot it was the lubricant and we stopped using it and it still happens. and i just wanna know any possibilities. i have poly-cystic ovarian syndrom and i dont think thats the problem. but idk whats up. just trying to get ideas. im gonna go to my gyn about it some time soon. any ideas?