I was faithful, but my hubby of thirteen years cheated on me a LOT. I would go to the doctor whenever I thought things were not right, and sure enough I'd have another infection of some kind. My doctors never told me they were STDs, and when asked, would give me wishy washy non-commital answers, then give me two prescriptions, one for me and one for him. At any rate, you may be sore because you just have a yeast infection that is staying at a very low level, or you could have something more serious, but you may want to get it checked out. If you are on hormonal birth control, that can cause severe dryness that leads to irritation as well. Or, if you're near menopause, lack of estrogen can cause this.