I have very sore nipples and both breasts are extremely tender. I have been gaining a lot of weight lately, but I'm not pregnant. Is it hormonal? Will this fade over time or should I go for tests?
Your weight gain could be part of the problem. If you are absolutely positive that you are not pregnant, you could track the pattern for a couple of months. It's not unusual to have increased tenderness before periods. Also make sure your bras fit properly. With your change in size, you might have some rubbing from your bra that is making your nipples sore. Because this is in both breasts, it is extremely unlikely to be cancer related, so you have time to do some detective work and see if a change in personal care products, bras, etc. would make a difference. If your nipples are unusually red, scaly, or peeling, then check with your doctor if simple home remedies don't make a difference.
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How to Tell if Breast Changes are Cancerous: A HealthCentral Explainer