text: Yes, there are exercises you can do.  You have a muscles on the chest wall behind your breasts that you can flex if you take something that has a spring action in the middle, maybe a ball would work and put your palms on it and hold it at chest level and press on it using the muscles in your chest to apply the pressure, not the muscles in your arms.  Flexing this muscles in your chest will firm up and help accentuate a nice breast line. Try different exercise to work those muscles.   The breast has a working milk producing organ protected by fat.  And if you ever have a child and breast feed; the breast feeding will actually tighten up your uterus. You will feel it tightening as you are breast feeding your baby.