On 20mg for celexa (citalopram) 11 days and have decided not to continue after further research. dr says i can just stop, pharmacist says to taper. who is right?

Would taper: Every patient is different, and there's no predicting until you try - so either of the two of them could be right. But the safest, most conservative bet is going to be to taper. You may try cutting the pills in half for half the dose each day for several days, then, going to every other day for a gentle tapering rather than stopping outright. That's just one of a couple possible strategies.