I work with a lot of athletes. Some are very experienced and some a just learning. #1 problem I've found with athletes that have a small chest is benching with hands too close together. This narrow grip puts and emphasis on your tri's and takes away from your pecs. At your size you should have your hands at least with ring or middle finger as wide as the rings on the bar. If you are doing that, great. If not that will help and will help with strength over time. When doing incline or decline the best way to keep the focus on the pecs is put 25lb weights under the end or top of the bench. This way you only incline or decline a couple of inches instead of what the typical incline/decline benches give you that change the muscle emphasis too dramatically. Also make sure you use a variety of lifts and change frequently. In addition to the above you can do flies, incline or decline flies, dips etc.