rear passenger door

[LongIslandLSE]

so tuesday of last week the rear pass worked fine, on friday the door did not open at all. i sat there and locked and unlocked the door numerous times both with the remote and from the door lock. anyone else ever have this, what could it be and how the f do i fix it. i am guessing the door panel has to come off but if the door does not open.......?????

thanks