Alright im 19 and I weigh about 68 kg. I work my chest every 3 days. When I work my chest I pick 2 workouts and do them till failure for 5 sets. Then the next time I work my chest I pick 2 different ones. That way I keep my chest guessing. But over the past 6 months I havnt seemed to see much of a change in the definition and size of my chest. I really want to get my chest bigger because its the weakest part of my physique. Any help would be appreciated.