I hate to ask personal questions but here it goes - are you by chance taking birth control pills? If so, they can cause the thin and delicate tissues in your groin/labia/vagina to tear easily and in turn cause pain and burning (my gyno likened it to hundreds of tiny paper cuts). It may not be a yeast infection but vaginitis. It might well be worth a trip to the gyno to have it checked out and diagnosised. It took me 4 different doctors to finally have my problem properly diagnosed. I now use an estrogen suppository every other night along with a prescription ointment that helps to reduce the inflammation.

Good luck and keep us posted.