The problem could also be gunfit. If the stock is too short, too long or has improper cast or drop it may be forcing you to shoulder the gun improperly.
It is expensive, but taking the gun to a knowledgeable gunfitter may be the answer. Everybody is built differently and guns rarely fit properly out of the box. A good gunfitter will check your stance and will watch you shoot the gun. This is the proper way to go about learning how to shoot.
I spent three years, and untold dollars missing targets before I saw the light and had my gunfit checked. The fitting session cost me $150 but solved many of the problems I was having. In my case the only adjustment was stock bending that cost less than $100.
Once you know your measurements you can have any gun altered to the same measurements.
My $.02 again
Geoff Ross