Hi. I'm a 16 years old girl. Since last week, I usually had a discomfort feeling in my chest and upper abs, sudden pain in chest (usually in the left side) and in some random parts of the body (such as left shoulder, left elbow, right chest). I feel tired sometimes, and sudden headache in the temple of the left side. I have been doing workout lately and some pull-ups, and I'm a skinny girl. I don't know if I'm having heart attack.