How much misalignment are you talking about? Where is it off? What are your measurements all the way around the door? Have you ever aligned a car door? You will need to buy or make a device to support/raise/lower the door without damaging it, since it probably weighs in the neighborhood of 100 pounds.
Personally, I would either bring it to a capable Chevy dealer, or capable body shop to see what they say. IMO, unless you know what you're getting into, you could make matters worse, and end up costing you more money.