I shoot a pretty good number of 3" 12 gauge and 20 gauge turkey loads each year testing various choke/barrel/shotshell combinations for my clients and my readers. That has added up to many hundreds of shells each and every year for the past 10 years or so.
I shoot all of them off my right shoulder and have paid a price for that. As far as can be determined, my retinas are okay but I have seriously torqued my spine and there is a definite twist in my back. it happens that the left-side back muscles are very much overdeveloped and put a lot of stress on the right-side back muscles. It's quite evident if you see my back.
(As an aside, my hearing is a bit better than normal for a man my age. I've used ear protection for the past 20 years.)
At this point the only "remedy" is to strengthen the right side of my back through specific exercises that target that area. That can help reduce the stress and hopefully, eventually the pain that's currently 24/7.
I am either fortunate or unfortunate in that I do not bruise, so there's never been any evidence of bruising on my right shoulder, just the constant torque of having round after round shoving my shoulder backward.
I started using various recoil absorbing products about 9 years ago when I first contracted with some shotshell companies to test their products. I met the man who invented the Shooter's Friend Recoil Pad and began using that product, even doubling it at times with some light guns. It certainly spread out the recoil and disbursed it over a larger area but did not keep me for getting "punchy" after a day of shooting 100+ shells.
A couple of years ago I was asked to do some pre-market testing for the Evo Shield recoil reduction shirt. I've used one ever since to help me "remain aware of where I am" after a day at the range. I still use the Shooter's Friend Recoil Pad & the Evo Shield and that combination helps a lot.
Recoil effects all of us even if we don't bruise or if we dont realize what it's doing to us. I'd urge anyone who's shooting heavy loads to take precautions, not only for your eyes but for your back and spine. Take it from someone who's learned but a bit too late to prevent the real damage that recoil can produce.
This is a wonderful sport but just like any other "contact" sport we need to wear appropriate protection.
"If he's out of range, it just means that he has another day and so do you."