My hunting buddy shoots a 16 Ga. Parker built on an "O" frame and the gun is very light with a good amount of felt recoil. We fooled around with very light loads and eventually came up with a 3/4 oz. and a 7/8 oz., both of which had a minimum of felt recoil.
I suggest that if you want to shoot without pain, reloading very light loads could be your solution.

Jim