Burning before period

I have had the oddest thing going on for MONTHS and no one knows what’s causing it...

about 10 days before my period is due to start, i start to get a very painful burning sensation in my vagina. It does not hurt to pee, in fact that usually alleviates the burning for a few minutes, and I test negative for UTI or other infectious. I don’t have very much discharge but if I do, it’s thick and white.

The burning stops the SECOND I start a full blown flow...(not spotting). My ob/gyn has absolutely no idea what could be causing it and I’ve been tested for STI/D’s and UTIs. I am not on any type of birth control and I am not sexually active.

Anyone else ever experience this before??