Random old guy keeps talking to ME HELP DONT KNOW WHAT TO DO!!? and now my shoulderhurts where he touched me!!?

yeah that is definitely strange. I think you should leave there. Don't go back for a while. Find a new place to study if you can because, he is definitely some kind of molester. And if you think he's put a spell on you pray to God to remove it. You'll be fine. Just get out of there now, get home.