door lock wont open 72 c10

[MacataQ]

hi all:
hoping someone here can offer some advice.
my passenger side door wont unlock with the key and the plunger(?) wont pull up or go down. inside handle doesnt do anything either. i have removed the inner door panel and PB Blasted everywhere i can reach. all the linkages seem to be connected, i think? i cant get very much leverage on it(cuz im old & fat) and usually working on it by myself.
anyone who has had this issue and got it to work, please let me know.
much appreciated!
Mac