I feel like something is in the left side of my throat for three days. could this be an std from oral sex?! i am scared. am i just parenoid?

Oral sex: .Depends in part on the type of oral sex in which you were engaged. If you performed unprotected fellatio on another man and ejaculate touched tissues of the tonsils or the posterior pharynx then it is quite possible you acquire one of several possible stds. If this was on a woman it is less likely. The best advice would be for you to go and be seen by your pcp and examined and tested if necessary.