Why are my breasts lopsided?

Because u r a woman: Most women have some amount of breast size discrepancy. This is normal and not automatically a problem. Some women have such a big discrepancy that cosmetically, it causes them personal concerns and anxiety. If this is the case, you may wish to consult with your physician to look into treatment options.

More glands and fat: One breast formed more glands (allowing for more milk engorgement) and fatty tissue, so ended up bigger than the other. If a woman's breasts were always equal in the past, and one recently got bigger, she should have the doctor examine the breasts to be sure that there is not a more serious problem going on, such as a tumor.