[32phil]

In my experience the bulge shown is caused by the frame snubber hitting the top of the axle bells caused by hitting a bump in the road or a rear end collision (one side or both)
I would start by removing the rearmost body bolts and making sure the body is not/no longer being pulled down or held by those bolts.
Then check the flat area on the frame from the rear of the firewall leg to just before the kick up.
If the frame is flat or close to it most likely the damage is limited to the area around the bulge.
The severity of the bulge will help determine the fix.
A good rule to follow is to look at the space between the top of the gas tank and the rearmost edge of the body typically about 3/8".
Remember on both sides of the body you must have enough room to slide the rear frame horn covers in.
One method I used placed the car under a garage door opening we placed a brace (actually 2 6x6 treated posts) from the floor of the car to the top of the garage door framing and then with a rear spreader bar in place added another 6x6 across the rear of the frame.
We then jacked up the car at the end of the frame and monitored how the frame moved upward. Obviously the frame at the bulge was not going anywhere because of the brace to the building. A little heat (gas tank out please ) at the bulge and some judicious blows from a 3 pound sledge helped. Once we had the desired spacing at the gas tank we stopped. The bulge was just about gone too. There was some wrinkling on the flange where the rear snubber is but also barely noticeable. On an original unrestored car it was fine.
Obviously several other methods can be employed the best being in a frame fixture without the body mounted.
As far as the door gap issue I've never seen one do that due to the bulge in the frame.
It looks suspiciously like an over tightened adjustment bolt. That's the one at the firewall that goes through the eyelet at the edge of the cowl about 1 1/4 up from the frame.
That one should not be too loose or too tight ...no spacers washers or anything between the top of the frame and the bottom of the eyelet. Tightening or loosening that bolt will move the rear of the door up or down. Hope this helps