He's right , if you have to lift the door to open it the pins and bushings are gone or over the years the door has been pulled down. Ive got special tools to align doors ,trust me tools youve guys have never seen before. what you want to do is try to lift the door up , takes muscle 2 guys will work or use a floor jack to lift the door closest to the outside.

This is all you can do . But check the pins first check to see if there is play ( wiggle the door up and down )