Wow, thats bad advice. If your shoulders are rolling forward into kyphotic posture you will be preferentially activating your anterior delts. Shoulders should still be retracted and depressed with chest elevated to maximally contract the pecs. You say you feel it in your chest, so perhaps you just described it wrong because your description fits the typical problem with chest training position.
To the op, check your posture as described above. Also, try hitting movements that emphasize the stretch like incline dumbell presses (full rom) and flyes. I always found that chest training, like lat training was very much a feel thing. This may be a funky thing I do but try throwing in medium weight sets of machine rows or another exercise between your upper chest sets.
I find that it helps maintain the correct scapular depressed and retracted posture on chest sets when your upper back has a pump in it and is tight. Plus it throws in extra volume for your upper back which is likely weak and contributing towards your shoulders taking over chest movements. Oh yeah, and hit some chest stratching movements in a doorway after your workout.