how do you get a BV

i recently cured my BV but it seems like i have some odor down there do idk if its yeast infection or another BV but last time i got a bv i believe it was because my bf stuck his dirty fingers and we havent had sex since i cured that so i wanna say its not from that but just to be sure can you get bv from soap or anything. i dont put soap in my vagina but it can accidently get in there . im about to go to the store and get monistat for yeast infection and just wanna make sure its not a BV