Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
This sounds like the ignition switch has failed if you cannot remove the key.Here is some info to help replace it.
Ignition Lock Cylinder Replacement
Push down on the allen wrench to release the tab on the lock cylinder inside the lock cylinder housing.
Important: The gears between the ignition switch and the lock cylinder housing must be in the correct position. Failure to do so will cause a misalignment of the gears in the ignition switch and the lock cylinder housing, which may result in a NO START or BATTERY DRAIN.