My breasts are not the same size. they have always been this way but recently the left has grown while the right has not. the ultrasounds ive done in the past indicate that there may be excess tissue. what should i do?

Same if same size: Breasts are often not identical in size & sometime the difference is dramatic. If your larger breast has had significant changes that point to a problem you would handle it the same as if bot were the same size. The doctors managing your case will come up with a diagnosis & plan of treatment. It could be a benign fibrous dysplasia or a worrisome problem requiring surgery for more study.