I have never had a pap smear should i?

i m 20 years old I am not ually active but was ually abused for many years which make me very anxious about getting one the last time i tried i was 12 and it was not a chose thanks to children aid i freak out so much that the doctor would int finish she basically only say the out side enough to see physical damage but i was not tested for stds now that im 20 i figure if there was any thing Major i would no by now am i wrong should i get one or try to ale st last time i made an appointment to talk to my gr about it i p out in his office anxiety attack what exacly do they do and does it hurt ?