Vulva discharge, it also causes weakness and backache

hi i am 19 and unmarried girl, i have been in a relationship for 3 years. We never had sex. But just kissed many times and whenever i used to talk with my boyfriend on phone or text messeage my vangina gets wet and heavy discharge occurs. We didn't talk anything dirty. Last time when we met we lay together and kissed eachother very badly from then whenever i talk him my vagina secretes badly and there remain heat like feeling around my vagina.. I don't know whats this i wannna get rid of such feelings and this discharge it also causes weakness and backache please help me .. Is it harmful and making me intetnally weak ..