What Causes Vaginal Discharge?

i have two questions the first one is i have a discharge in my underware on and off its sometimes milky white and sometims there are stains of yellow on my panties i was wonderin what it could be ?



my second question is i have a small pimple like thing near my privite area it doesnt hurt or anything like that just sometimes gets a little bigger then goes back to small what do you think it could be ?