I have this brown paste like yeast in my vagina and butt, it is very itchy and has a bad odor. The itching gave me a rash in butt. I never had sex! ?

BV? Foreign body? Probably not yeast, or maybe yeast plus something else. Yeast infections usually itch but odor is uncommon, and brown discharge doesn't fit very well. Strong vaginal odor usually means bacterial vaginosis, an overgroth of mostly normal bacteria. But BV is rare in virgins, although it can follow oral sex. A foreign body, like a forgotten tampon, can do this. Stop guessing; see a doctor ASAP.