Igniton Switch is Locked

Anybody got any ideas on why my ignition switch is locked. I can start the 91 S-10 , but I can't turn the key back to shut it off. I cannot get the key out either of course. Is there anything I can do besides having to take the steering wheel off to get in there?

Thanks in advance

try playing with the linkige for the shifter if its out of line then it may prevent the key from coming out like if you left it in drive.