A few exercises that will help make your breasts bigger without going in for surgery are.
Push-ups, Push-Ups help to strengthen the muscles called the pectoral muscles which are located below the breasts.
Lifting Dumbbells.
Lifting Dumbbells is another great exercise for increase breast size by also strengthening your pectoral muscles.
Although not an exercise but you should try eating more food that contains estrogen to help make your breasts bigger.