Don't try to push a door like this back onto its track by hand. A double door built to the sizes common in Weddington's 1998-era garages is heavy enough that a section coming free while you're under it is a real way to get hurt, not a minor annoyance. If the door is only an inch or two off and the opener still has power, you can sometimes release the opener arm and see if the door slides freely by hand - if it doesn't move smoothly on its own weight, stop there and call it in.
If you want the general mechanics of how a door comes off track and what usually causes it, the broader write-up on [garage door off-track repair for Charlotte](/garage-door-off-track-charlotte-nc) covers that without the local specifics. The honest limitation here: we can't diagnose a bent track or a snapped cable over the phone with any confidence. Photos help, but someone still has to put a level on the track in person before we can say what parts the job needs.