no offense intended i disagree with every one on the padding suggestions. i want as little between my rifles stock and my skeletal frame as possible. ive been shooting around 15-20 rounds from a 505 Gibbs every Sunday for the last few months. just today i fired 30 505 Gibbs cartridges divided between two rifles and another 12 rounds from a 416 RM. in my opinion soft pads such as jackets, coats, and any other overly soft pads allow the rifle to accelerate before hitting your shoulder which is just going to make it worse. now im not sure about the PAST recoil pad because ive never used one and maybe it works but again i dont like having something between me and the stock.
a few things id recommend you do to prevent this injury in the future. first, stop shooting from the bench unless your going to use a lead sled (i love lead sleds for big bores). second, spread the shooting out a little more. shooting 25 rounds in one hour is too much for my liking, i broke up the 42 cartridges i fired today over 3 hours. not to mention that shooting quickly heats your barrel up which can change the POI which means if you adjust your optic for a hot barrel it will be off when your barrel is cold.
-matt