If your a girl then yeah, you are going through that stage in life that you are becoming interested in that kind of thing and curious as to how it feels. If your a guy, then.... why are playing with your nipples?
It is normal for your breasts to get larger as you grow.
Swelling and tenderness of the breasts around ovulation time can be normal.
yes i have a 14 year old daughter and i get mad when she sits in front of the mirror and plays with her breasts, girls love doing this. it is perfectly normal
No.
depends on when you started puberty.
Yes. As breasts grow, it is normal for them to be tender or a bit sore.
Yes.
yes
Yes
Yes
Yes, it is completely normal, especially if you are athletic.
yes, very normal