key gets stuck in ignition after new battery installed

About a month ago, my key was getting stuck in the ignition. it is now happening everyday. i thought it was the cylinder and ordered one from a Cadillac parts place. Called a locksmith, he said the key and cylinder are fine, showed me how to release the key manually using a screw driver. Said it was a sensor. Called Cadillac maintenance company, they said the battery is bad and there is not a sensor in the steering wheel. Had the battery check, and purchased new battery today. Key was stuck in ignition, had to use a screw driver to remove it. Help!