If you take the door panel off with the window down and look in side, you'll see the window is held in place by two tabs/tracks on either side. These tabs/tracks are out of alignment and bend easily. This is what causes the window to tilt forward/backward causing it to bind. You'll need to bend them ever so slightly to attempt a re-alignment. Move the window up and down as you make adjustments. Once you have it just right, lube the tracks and replace the door panel.

Just be careful in here, take it slow and you should be good to go.