Like said most of the issues is genetic...some muscle groups are very stubborn in some people. As well you need to lift correctly....as an example if you cant seem to get your delts out of the bench press and cant seem to target the chest...doing #1 and #1 wont do a thing...you need to learn how to bench correctly. Once you do that you need to get very good at lifting and get to a point where you are making significant progress strength wise. No matter what you have been told you can isolate the chest all you want but you wont build any significant size benching 135lbs.

P