Are there any natural ways to increase breasts?

I'm 16 and my boobs have been a 34 AA since I was 11. I'm 5'6 and weigh 114 pounds so i'm pretty thin if that has anything to do with this. I've tried doing excersizes and massages and eating flax seeds but they still aren't growing. My younger sisters are 14 and 12 and their boobs are both bigger than mine. Is there anyway they can grow without surgery?