The door that won't open, or opens and then drops halfway, is almost always a spring problem on houses this age. You'll hear it before you see it - a bang from the garage, then the door refuses to lift past a foot or two, or the opener strains and reverses itself.
A door that's noticeably heavier on one side, or that someone has to help lift by hand, points to one spring gone while its twin is still holding. That's not a small fix-it-later problem. A single working torsion spring under a door built to the standards common around 1957 can snap a cable or bend a track trying to do the job of two.