Left breast larger than the other ,pain in right arm pit relation? Bra size question?

It is normal for one breast to be slightly bigger than the other, but it shouldn't be that much of a difference. If it is a whole cup size bigger as you say I would go to the doctor and have it checked just in case. Since you are 21 you should find an OBGYN and go to one at least once a year.

Hey Rachel,

I really don't think you should worry at all. It's completely normal for one breast to be larger than the other, often noticeably so, and what you describe is well within the normal range. The risk of cancer at your age is extraordinarily small, absolutely miniscule, so I wouldn't fret about that. The pain is very likely to be related to hormonal variation and the recent breast growth, all completely normal. The one recommendation I would make is to minimise the time you wear a bra - this is proven to help the great majority of women with chronic breast pain but more relevant to you it will eliminate any role your bra is playing in your recent discomfort. (As an aside, it's also the best way to prevent sagging!). As for whether to go up a size, that only you can judge - there's no right answer, if you're really spilling out on the larger side it may be time for a change, but otherwise stick with what you've got and just don't wear it more than you really need to.

Bottom line though - there's nothing at all to worry about, keep smiling! :)

See doctor possible issues .pain under armpit needs looking into.

Larger bra as temporary measure.