WHY WONT MY CAR REVERSE?? on 1992 Toyota Corolla

I went to the store and was trying to reverse my car into the parking space when it wouldn't move i thought i was in a dip or something but it happened again in a different parking lot and now every single time i try to reverse it wont unless i force it. What can be the problem?

Asked by for the 1992 Toyota Corolla
internal failure. have a shop check it and give you a bid.