What can i do to make my breasts the same size I am nearly sixteen and there's about a cup size difference in my breasts its making me feel very insecure is there anything i can do?

It may be that you're not fully developed yet - and your body hasn't 'settled down'... While women's breasts are rarely identical, if it's affecting your self esteem (which is apparent from your question) - there are two options open to you. You can either wear a removable insert inside your bra, or opt for surgery to even out the size. Make an appointment with your doctor, to discuss your situation, and find out the best option for you. Only a qualified doctor will give you accurate, expert advice !