Smoker. Heaviness In Chest, Painful Hand. Am I Suffering From A Heart Disease?

Hi i am 27 years old , a female and smoker, heavy smoker. I finish 20 cigs per day. I feel tired all the time, no matter what i do. Sometime i feel like there is something heavy on my chest and i cannot breath at all, i feel it along with pain. But not strong pain, sometime, a strong and quick pain would attack me, really like an attack and i would even react toward it. Sometimes i feel that my right hand hurt me more than the left one, and the left one hurts me but not that strong at all. I did check on my heart before almost 2 years and everything was fine, nothing weird. But i am really worried now, especially that sometimes i feel real strong pain on my back and on my sides