Is Tissue Expansion Or Grafting Good For Burn Scars On Chest?

i am 22yr old girl.i have a burn scar on my chest.because of this scar the growth of my left breast is 50% less than that of right.its because under my left breast bit of skin is gathered and hard.i am having this scar since i was 7months old.doctors have suggested me for tissue expansion or grafting.i would like you to help me which treatment out of the above 2is best and which has less of side effects and if there is another best treatment available.