Hi. I think I know what your problem might be. I have a bartholin cyst, and it does what yuo are describing after sex, before/after period. The cyst can be caused by over 60 types of bacteria...Some std's some naturally occurring in body. From what i've read, this is mostly due to bad luck, unfortunately...
Try soaking in a hot tub for a bout 15 minutes...This usually helps me, but actually, right now, it is very irritated, and the baths aren't working as well
do you know anything new?
Hope this helps.