Depends on if you're a girl or guy I guess. Isn't the heart closer to the right side? Could be something to do with your heart. Also showers and exercise tend to have similar results- more heat in the body. Maybe heat has something to do with it. Well I wouldn't be much help here I see. I don't think it's that big of a deal. Try taking a cold shower and see if that makes a difference. You could have a pulled chest muscle, if that's possible. Ack my answer is terrible.
It could be something to do with puberty. Men can also get sensitive around their body just like girls. I would in any case visit a doctor, especially if the pain is really bad,because what is normal for a girl might not be that normal for you.
If you take hot showers it will burn the nipple, or if you wear unfamiliar clothing one day it could annoy the nipple as well
haha, im a male. n idk, im geussing its something with puberty?
yeah that makes sense. Growing pains. Drink more milk man!
It's closer to the left. :)
Curses. I fail.