When you went to get a shot, the words, "This won't hurt a bit," became a conditioned stimulus when they were paired with pain of the shot, the unconditioned stimulus, which was followed by your conditioned response of getting the heck out of there.
Kada ste bili na cijepljenju, riječi "neće nimalo boljeti" postale su uvjetovani podražaj kada su bile uparene s bolnom inekcijom, neuvjetovanim podražajem, kojeg je slijedio vaš uvjetovani odgovor bježanja.