if youre at all mechanically inclined try taking the shifter off (its just two screws, but when you pull it up off the shaft watch out because the button likes to jump out) then pull up on the white piece sticking out, have some paper towels handy, its pretty greasy. i had a problem with that shaft not fully coming up and when it didnt, my key would not come out of the ignition, i put in an aftermarket shifter which may have made the problem worse, so i had to add an additional spring to help pull it up, however if youve got the stock shifter, it may have just gotten stuck as a one time thing, thats where i would start
let me know if you need further instruction taking apart the shifter (all it takes is a phillips head screwdriver)