If you are looking for chest exercises you can do at home without weights you have a lot of options. If you are not strong enough to do push-ups yet, you can simply do wall push-ups. Put your hands shoulder width apart on the wall with your feet a couple feet away from the wall. You will then mimic a push-up but it will be much easier because you won’t have gravity fighting against you.

When wall push-ups become too easy find a counter top or back of the couch where you can do push-ups. This will be slightly harder but will work the chest even more.

Tightening up the muscles of the chest will produce more firmness in the breasts and will lift your breasts the more you train your upper chest. Now don’t think that you will look completely different, the lift here will be very minimal and you will see it more if you have smaller breasts.