If you haven't tried it, you won't know. Walking = first step in losing weight, AND feeling good about yourself. You start losing weight overall, depending on your body shape (women have different body shapes, you can't control which to make bigger or smaller except surgery) What exercises do you do? FOr how long? How much do you work? Lookup a dietician or even online for healthy food choices. What does your mother cook? Try decreasing the portions.

Your chest is made of muscle, glands, and fat. Making it bigger is not possible except surgery, hormones, and other unnatural ways