Hey Michael. I was having severe shoulder pain in my string shoulder from shooting. I was trying to just bear through it, but it was getting worse.
At the time I was shooting a 60" 49# static tip recurve. I switched to a 66" 52# mild R/D longbow and no more pain. The draw is so smooth and with the long limb length there seems to be less stress on my shoulder.
I don't know exactly the physics involved, all I know is I'm pain free and shooting as much as ever. Could have been the geometry with a certain bow and my body type, but going to a LONG longbow worked for me.