Sounds like chest muscles or ribs out of alignment. You can have her checked by a chiropractor who can tell you for sure if that is the case. Heart related chest pains are usually in the center of the chest and radiate outward lasting 30 minutes or longer when a heart attack occurs. Make sure that she is getting enough B vitamins and D vitamin.
I would tend to think this is more puberty than anything else. True heart related chest pain in childhood/teen years is extremely rare and there would have to be severe heart disease for that to be the cause of the dhest pain. Chest pain is caused when the heart is deprived of oxygen, young people don't usually have that problem. Also chest pain in that sense would be lasting a lot longer than you describe and would disappear with rest; kids with heart related chest pain don't push themselves to that point. I would not consider sending her to a chiropractor because once you start going, you have to keep going. I would just give this some time and don't make a real fuss over her which can aggrevate the problem. If she is having a REAL problem, believe me, you wouldn't be questioning it on here, you would know.
It's scary but very common around puberty, I remember I used to get sharp brief chest pains once in a while. I really wouldn't think it's heart related unless she has other associated symptoms like dizziness or passing out. Try googling "precordial catch syndrome" and see if that sounds like the same thing?
Hi, I am 13 - almost 14 - and I have been having these types of pains for about 3 years now. My father is a Chiropractor and does his best to figure out what is causing them, but answers have been limited. However, from the little results we have found it doesn't seem like anything serious and we are hoping it will just pass. For the first two years, the pain was very rare and short. Lately, though, they occur every day. They don't seem to hurt as much as they used to but have lasted as long as 10 minutes. It really varies. My father has put me on various supplements which seem to help, but it's never been a real problem. I'm sure you have nothing to worry about.