Why do i feel tenderness on my nipples?

Why do I feel tenderness on my nipples??
And I mean like major tenderness..it hurt even when
Its being rubbed against my bra!
And pressure in only one of my breasts?
And well I don't know if it has to do withmy period
Bc my period come till like the...

20th...
Could I still be growing?

You're pretty young, so yes, you could be a late bloomer

It could also be that your cycles are becoming irregular and you will be starting sooner than you expect

No you sooo pregnant. That's how I found out I was.

Your age? If you're young (like, say, a teenager), you're still growing, and you are going through some hormonal changes. That would probably explain breast tenderness. BUT... there ARE some RARE infections you can possibly get, like Mastitis. Do you have a discharge from your nipple on the tender breast? Is there a localized pain? Any lumps in your breast? Have you had any injuries, I.e., been hit - or bitten - in the breast? If you have a discharge, I would recommend going to a Gynecologist ASAP. Otherwise, give it a few days and see if it clears up by itself. If the pain persists, see a Doctor.