As far as std's are you certain he's been checked for std's? (quick test is to ask him how he dealt with the cotton swab - to test men for std's they have to stick a swab up a penis, and men get so wonky about it... I can't imagine how they'd deal with the "duck lips").
And not to startle you or anything, but there are a few conditions that could cause pain during sex one is called vulvodynia -
vulvodynia webpage for more info and the condition can vary alot. Another condition that could cause it is
endometriosis.
Now of course the pain you have doesn't necessarily mean you've got either of the above conditions, but maybe the information on those pages can help rule out or rule in what's going on with you. If the pain persists, definately see a doctor. There is a slight chance it may have to do with the pill you're on, and how it's affected your hormones, too.
Otherwisse since you said you're wet enough and have foreplay enough, i'd guess you'd have those bases covered, though it couldn't hurt to buy some lube and use ample amounts of it and see if that helps.