Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Do you have power to anything else? Headlights? Radio, etc?
Have you checked the battery voltage?
The shift lock is electronic. It won't let the shifter move without battery voltage.
It sounds like you may just have a dead battery. If there wasn't something left on you might have a battery draw.
Also, batteries tend to die with temperature changes. If it's getting cold where you live, it could just be time for a new battery.
Just wanted to check and see if you need any additional info.
Please let me know if you do, and if you are ready to rate.