It is really hard to make a diagnosis only seeing two of the four corners. I don't know if the entire door is simply shifted towards one side or twisted in the opening.
Some things to check out: Do a visual inspection of the springs. I have had them wear out and break a couple times over the years and when one side does that, the door immediately becomes twisted in place and is hard if not impossible to open. I would also put a level on the headers and jack studs of your garage opening and verify things are plumb and level to help diagnose if settling is an issue. When residing my house a few years back, things weren't lining up around the garage door and I threw a level on it only to find out that there was a three inch difference in height from one side to the other. I ended up jacking up the low side of the garage to get things plumb and then my garage door which worked but didn't seal really well before suddenly sealed very tightly.
