Hi Cal - I don't know that this will work for everyone, but I had the same problem. I learned that part of the cause in my situation was poor external shoulder rotation. Rather than figuring out different angles, exercises, positions, etc to activate less shoulder as I had for so long, I got to the root of the problem. For me it was lying on the floor with a tennis ball under my shoulder blade and rotating my arm while moving the ball. It hurts but it helped release tissue that was causing my shoulder to stay forward and take the majority of the load on chest movements. Pm me for videos if you'd like. Hope that helps!
My front delt would always get more sore day after doing incline barbell than my chest did. Fixed inclined barbell racks are usually too inclined. I feel major things to reduce activating shoulders would be lower the incline. Well below 45.. like 20-30 and don't flare your elbows out to the side when you are pressing, keep them somewhat tucked. On the fixed incline racks, it helps to slouch as much as you can to lower your body's incline. There is usually a pretty big gap from the seat under the small of your back.
yeah as snrose was saying a lot of people set the incline much higher than it has to be and you end up using front delts a lot more than you should. I put the incline up one or two from the bench being flat. Also try using less weight and makes sure your form is good a nice good stretch at the bottom of each rep with a 1-2 second squeeze at the top this stops u from jerking the weight around and possibly using your shoulders.