Just as weight loss takes time, so does building muscle. Muscle growth requires a combination of commitment, cardio exercise, weight training, a healthy diet, and rest and recovery. In order to build up the chest muscles, it's also important to work the other parts of the body too as it will increase your metabolism and stimulate greater muscle growth.
Eat more. You should add about 500 calories to your daily caloric intake, incorporating plenty of lean protein. Eat larger portions of whole grains, lean protein like chicken or fish, unsaturated fats and plenty of fruits and vegetables.
Consume protein. It's a common myth that protein builds muscle; it actually helps to repair muscle tears, which happen during strength training. Protein shakes can help recovery and are a good source of extra calories.
Lift weights, targeting your chest area. You'll have to start out at a lower weight, so try ten or 12 pounds at the beginning. Limit your repetitions to six to 12 per set for the most muscle growth. It's also important to work the rest of your body for maximum muscle growth and a better metabolism.
Change up your workout. Once you've been following a routine for about a month, or when the sets get too easy, it's important to challenge yourself. Increase your weight by a couple of pounds, enough so you are working yourself hard for up to 12 reps.
Rest and recover. In order for your body to build muscle it needs rest to repair itself. Being well rested also gives you more energy for a better workout.
Do cardio exercise. Cardio is important to stay in shape and burn calories, but you don't want to burn both muscle and fat. Three cardio sessions a week, lasting no more than 30 minutes, will help promote good heart health without causing you to lose weight.