Sounds like the same problem I have had with my "88 Buick LeSabre. The mechanisms in the doors get sticky and need lubricating. Is it cold there? Mine acted up more in cold weather. I got one door to open by waiting for a warm day and banging on the door from the outside near the door handle. The vibration made the mechanism move and I could at least get it open. The other side had to be released from the inside. It was quite a chore finding the right part of the mechanism to move, and equally challenging getting some WD40 sprayed into the right place to loosen it up. Be patient, I wouldn't start cutting and bending and breaking stuff in there. It'll only make things worse. (the WD40 is only a temporary fix, by the way)
The real fix once things are open is to take the mechanisms right out and clean them in solvent and lubriplate all moving parts. It can be a big job though and some riveted in parts may need to be drilled out. I didn't do that with mine.
I got mine open and put a For Sale sign in the window
(its got 370,000km on it so its time to go anyway (that'* 220,000 miles) Bought a '95 SSEi to replace it. I'm dismayed to hear I might have the same annoying door propblems in the future.