I am 25 and my chest is 38 inches. Can I widen my chest to 42 inches doing pull ups and chin ups or any other method?Both pull-ups and chin-ups are two of the best exercises for back and overall upper body conditioning.
However, they target the muscles a bit differently. Both exercises will work the lats (latissimus dorsi) and secondary muscles which are involved are arms, shoulders, abdominal muscles and forearms.
To widen your chest the best exercises is push ups with variations like normal, close, wide, incline push ups. Use push up stand which helps to expand the chest muscles.
Another useful exercise is dip bar exercise (Dip (exercise). There are two popular variations for chest one is parallel push up and another is swings which is my personal favorite but it requires a lot of skills and practice else you could end up injuring your shoulders.
Rest are the workouts that are done with gym equipment like bench press, dumbbell flys. Refer Bodybuilding.com - Huge Online Supplement Store & Fitness Community! for various chest workouts.