How to fix my 2002 pontiac window stuck in door (manual)?

Yes take off the door panel. Do this by looking for all the screws that attach the handle, usually underneath. The door panel itself is usually held on by clips. So use a flat head screw driver to CAREFULLY pry it off. You do not want to scratch the paint or break the clips, and they are usually plastic.
But be very careful when working with the window! If you break it you'll have to buy a new one. I suggest that before you start this operation, place something soft and squishy on the ground. It's also nice to have a second pair of hands, just in case.
Since this is a manual door, the window has probably come off of the track. You have to look how it is held in the track. Some cars use glue on plastic clips. If this is the case, snap the door panel back on and go to an auto-parts store or auto body shop for the correct glue, and possibly new clips.
The other choice is that the mechanism is stuck. If the handle turns, but nothing happens, then you won't have to play with the glass, but you will have to figure out how the handle attaches to the gear mechanism and put it back in order. If the handle doesn't turn and the window is on the track, then something is probably jamming the gears.
No matter how you wind up fixing it, now would also be a great time to lubricate the gears.