I've been having heart palpitations, chest tightness, burning sensation like heart burn, horrid pains in my shoulders and neck, dizziness and fatigue.

I run XC, I'm 16, life is very stressful, and heart disease runs in my family. I'm worried, but with so many people being hurt and diagnosised with diseases around me I almost don't wanna know as well as being told it's just stress or anxiety, I'm half tempted not to go. I wanna hear what you guys think and if you have an suggestions of what it could be, please tell me. Thanks!