the car door must be open almost all the way, for the gas door to release
The easiest thing to do would be to bring it to a local mechanic. They will be able to figure out why the door will not open and fix it without further damaging it or the car.
Remove the door panel, find and repair the lock linkgage.
Don't open your car door into traffic. Use the other door.
try and remove the door panel, you may be able to just pull back enough of the panel to manually open the door, they you can remove the rest and replace the bad parts.
Try checking for a child lock. If it's on, it'll keep the door from being able to be opened from the inside. Happens in our car all the time.
Take off the door panel. the plastic clip that holds the metal rod to the door handle came off or broke off. replace it.
Do NOT pour hot water on a frozen car door, your window will definitely not make it! Cold window in frozen car door+hot water=broken window. Try taking your ice scraper and actually prying the door along the seal to get it to pop open.
to fix your problem, remove the door lock and buy a new car
open the car door with the handle
Go in from another door and open it from the inside.
First you need to know what is wrong with it before you can fix it.