Exercise For Widening Chest. But like others have stated, you're 15 just keep hitting the weights and packing on muscle and dont worry about that stuff right now. Squeeze your chest to return to the starting position.

Begin the exercise by widening your hands on the floor. A muscular, broad, sexy chest is the cornerstone of a perfect male body and here are 8 most effective bodybuilding exercises to build an awesome chest. Always talk to your doctor.
I agree, my favorite chest exercise for a wider chest is wide grip bench press.
If there’s anything you should focus on to make your physique stand out, it’s building a thick, wide, 3d back that demands respect and makes heads […] To get wider shoulders, focus on standing up straight with your chest out, since good posture will make your shoulders look wider. To avoid this you can do the straight arm variation. The most important execution of the movement is in the elbows: