Given your medical condition, this is actually very dangerous and needs to stop pronto.
It's time for a prong, as he is six months old.
Make sure you learn exactly how to fit it and use it properly.
Leerburg | Prong Collars & Fur Saver Collars
Oh, and lose the harness. That only encourages him to misbehave.
Have him sit to go out. He absolutely does not get to go outside or anywhere until he sits down and is calm first. He jumps, the door gets shut. You open the door, he should not move. He does, the door gets shut. Do this until he understands that you control the door, and he goes out on your terms, not his.