I, by no means, endorse this method, but as a young man a real body man with 60-70 years experience showed me this technique. Open the door, put a 4X4 in place at the door sill and after rolling the window down grab the top of the door and push it in towards the body. You can move the board around to gain leverage in different places to tweak the door where you need it. This method has worked several times in the last 50 years. He explained that the wind, kids, hard usage can bend the doors causing them to be out of proper alignment. Good luck.
