If your garage door won’t open, it probably has a broken spring. The classic symptom is that it only opens a couple inches and then shuts off. It will feel extremely heavy, as the spring is used to counter balance the weight of the door (which is probably 150-500 lbs).
Castelgate Garage Door Services specializes in garage door spring replacement. We carry only “high cycle” springs intended to last at least 20,000 lifts. All of our springs carry a five year warranty, and we never leave a job with the wrong spring on a door!