So i just got a 1994 grand am SE a week ago. the key the guy gave me works fine in unlocking the door but for some reason it decided not to work 10 minutes after i unlocked it at work. i'd put the key in and turn it to unlock and it turned a half turn and then jammed up. i sat there for an hour trying to figure it out to no avail. finally had to call a locksmith. what could this be? please help!!!!!!!