What Causes Vaginal Burning?

Hi ,I am having continuous burning in vagina from last 4 months...it goes and come back i have tested urine 2 months before it is normal.recently my gyn has given me cream Globan-g for applying in vagina and also 3 tablets o insert in vagina ...i have repeated the course agian ...but burning come again sometime ...it is not continuos and sometime travel towards anus ...so i am really confuse what is this.can you please explain me what steps i need to take?