When you are about to reach puberty during your teenage years your breasts starts developing. This is medically known as tanner staging. There are different stages like thelarche, menarche, pubarche at which your body grows.
Reasons for breast pain:
1. There is a formation of a small breast bud below your nipples and then slowly it goes on increasing and your full breast is formed.
2.The stretching and expanding of the breast is also a reason for you to have breast pain.
3. There is a surge of oestrogen and progesterone during your periods, all the hormones are at a rise and then they come to a lower phase.
One of the symptoms and signs of PMS is breast pain. A little bit of breast heaviness/ tenderness is very normal, similar to the way you have bloating, just before your periods, during your periods, the initial few years of your teenage life is normal. But if you see a lump in your breast, any skin change or discharge from your nipples these are not normal. If you are facing excessive pain where you have to take medicine for that pain then you should definitely consult your gynaecologist because it is not normal.