14 year old female, mild chest pain, heavy arms and legs, regularly exercises

Hi, my fourteen year old daughter recently began to feel a mild pain in the upper, middle part of her chest. She found it hard to describe the feeling, but said that her fingers and toes felt disembodied from her and her arms and legs felt as though she had been lifting weights. The pain was worse last night and she now says she cannot feel it as much however I would still like to know if there is something wrong? Perhaps something dietary, I am not too sure, she doesn't suffer from anaemia but sometimes has fainting episodes, could these be linked?