Burning down below

I just wanted to see if anyone experiences pain like i do, i have chronic episodes of burning down below, feels like its my vulva or urethra. The pain usually starts after a pee but i dont know if its my skin reacting to the pee or just a uti because 80% of the time there is no uti.

The burning episodes are so severe it feels like my vagina is being burnt with a pair of hair straighteners, it can last for a hour to 8 hours, it is unbairable and it hurts then to hold my pee in.

I have seen urologists and gynaecologists all have pretty much let me down. Its been put down to possibly painful bladder syndrome, vylvodonia etc but effectivly i have no doagnosis and no treatment plan.