Help!

Okay so I've got a question. For a long time now, my vagina has just been very weird (probably a few months now). My discharge is very thick and white and the area surrounding it is very itchy. It isn't a yeast infection, it isn't a UTI, and it isn't an STD (my boyfriend and I have sex, but it is always protected and we have never done anything with anyone else). This is becoming very annoying and, when I itch too much, painful. I don't know what this is or what to do! Can anyone help?