It burns when my bladder gets full

hello i really need help i keep gettin this vulva burning and ureatha burning it doesnt burn when i wee but it burns when my bladder gets full and after i have urintated this had been happening for the last 2 years now i have been tested for stds all clear b.v,t.v and thrush and yeast infections all clear i have also had a ureatha dilation that didnt work :-(
when my bf touches me dwn there it burns all at the sides of the opening of my vagina it burns when i have sex and after for ages and ages talking about 4 hours.i use ice to numb it that soothes it until i take the ice of and its back again also when i have had the ice on there and i go the toilet it burns when i wee realli bad which is making me wonder if i have i.c im not sure weather i have ic or vulvadoynia it also burns to wear tampons sumone please help me its really making my life hell xxx