Key won't turn to start car. Please help!!!

[ave]

When I moved the shifter into park it seemed like it didn't click all the way. I really didn't see it a problem till I got back into the car to start it again. When I put the the key in it took a little force as it wasn't going in. It won't turn. I tried turning the wheel but nothing. I also took the shifter off and press the button in there to move the shifter back and forth buy no success. What can it be? Please help!!!