Who has experience seeing how people react when they get shot? I am not speaking from experience because I don't have any seeing people really get shot, but I've seen lots of dramatized shootings on tv and in movies in which the victim puts his hand over the wound, basically to hold himself together.
In Oswald's case, he was shot at the bottom of the 7th rib at the costo-chondral junction.
So, since that's where the bullet entered his body, what would cause him to clutch his right upper chest when it was nowhere near the wound?
Even if you want to say that he was pressing his forearm over the wound, why bring his hand up so high?