Your springs may be broken. There are two different types of springs. If your garage door springs are located horizontally at the top of your garage door then it is called a torsion spring. You should check for a gap in between the springs to indicate if they are broken. If your springs are located at either side of your garage door, they are called extension springs. Look to see if a piece of them is hanging on the side of your garage door to indicate if those are broken. If your garage door springs are broken then replacing them is a dangerous process if you have never done it before so you should seek a professional to repair or replace them.
Call McKinney Doors: 972-222-2345