What Causes Heart Palpitation And Painful Shoulder Blade?

My heart rate has been 100-110 and i have a pain in my left shoulder blade area and when i take a deep breath in it kind of hurts in my left chest area.. i havent been sweating nor have i had any pains or discomfort in my right side what so ever so i am not suspecting a heart attack.. any ideas what else could be wrong or could it in fact be a heart attack.. i am 34 years of age and i am a smoker and i drink occasionally.