2008 Chevrolet Impala - Key gets stuck

Have a problem with my 08 Chevy Impala. My car won’t start and the key gets stuck and the only way were able to turn it on is by giving it a jump but the next time we turn it back on it happens again. Mechanic looked at it and put a new starter and worked for a bit but itdid the same thing the next day, key got stuck amd car wouldnt start, mechanic said it was the ignition switch and worked for a little bit but by the next day it did the same thing, said we should have a locksmith take a look but don’t want to keep spending money on something it doesn’t even need. A week before my car didnt start someone broke into my car and took my custom stereo so dont know if that has to do with anything since they yanked it out really good. Please let me know what you think it might be.