Hello, I Am Having Vaginal Discharge That Smells Like Vinegar.

Hello, I am having vaginal discharge that smells like vinegar. I have been having it for a few years now and didn't think it was unusual. I went to my doctor, who first thought it was a yeast infection (which it was not.. after going through treatment) and then a bacterial infection (no change after going through treatment). She tested me for STD's (although I am not sexually active) and another time for other infections (there were none). I am unsure of what to do because it still persists. There is no itching or redness, and it is a white-yellow clumpy color.