i had issues inserting and removing my key (and a few times was certain that it would not go back in) just like you described.
the problem was the switch and tumbler were no longer lined up and turning correctly. once the new switch was put in, everything was good again. no issues with the tumbler. you'll be certain you got the wrong switch when you get the old one in because the line for the tumbler will be way off...
(old one on the left)
when i pulled the old one out, i had to put the key in and turn the tumbler further to get it lined up with the new switch, fyi.