Hi. I am fifteen years old. I am a little out of shape, but not extremely. I am about five foot, two inches and weight around 140 pounds. I walk for about an hour everyday at a fast pace. Yesterday, I danced for two and a half hours from 11:30-1:00. I was sweating, but I wasn't pushing myself exceedingly hard. It was a good work-out. I relaxed the rest of the day and around 9:00, my sister asked me to do one more dance with her. I did an during that dance, my chest started hurting severely. The pain continued until I went to bed. Even today, I have mild chest pain. Is this normal?