FYI, when it comes to door locks in the winter, the mechanism can get frozen. When you first attempt to pull the handle and it does not move with the usual force, never force it your almost guaranteed to break the mechanism. You can try the door on the other side and if that doesn't work and you have a wagon, you can always crawl in thru the rear hatch ( had to do this only once all other times the other door worked). As a precaution now I follow the weather forecast and spray WD40 in my keyholes, door and hood clevis mechanisms, its good insurance.
I learned the hard way, broke my drivers door handle, had to tear the door panel apart the only high note was that I found the original build order ticket inside the door.
Chiboy