Big ribcage,please help, doctor advice wanted?

I have these over sized ribs that i want to get rid off. im 12 turning 13 in 12/14/10 and its so bad that when i lay straight down and hide my chest i cant see my stomach because of my ribs. I'm female and i know its not pectus excavatum because i don't have that cave. Im 5'3 and weigh 104 pounds, please dont tell me to get fatter because i really dont want to, if anything i want to get skinnier. i don't know how to get rid of it and im thinking plastic surgery. im well aware of the risks and my father wants to find another solution and if worst comes to worsts he lets me. i asked my doctor and he just came up with some excuse like i'm beautiful as it is and that he doesn't want to hear it and he practically shoved me and my father out of the door.