I Am 31 Smoked 15 Years Don't Drink Have Heart

I am 31 smoked 15 years don't drink have heart problems in family notably stroke in father's side of family my dad has had 2 strokes I every once in awhile feel like my chest is going to explode and keeping me from catching a full breath having to breathe very slow I'm not sure if it's a panic attack or could be something really wrong I know it's semi painful a 5 of 10