95 BPM and anxiety of heart attack.

Hello Doctors, I've anxiety of heart attack, i check my bpm every now and then. From today morning i felt my heart beat is fast so i checked it by putting my hand on chest and counting the beats. A week back i had burning sensation which started from chest and spreaded to whole body. I immediately went to emergency room they checked my ecg which was normal, i did troponin test as well which showed negative. Please keep in mind that I've gas issues. I'm an active person i play cricket l, i walk average 3KMs everyday. And while doing any physical activity i never feel out of breath or tired. Sometimes i do get slight of pain between the are of left shoulder and chest, which last for 1-2 seconds. I smoke 9-10 cigarettes everyday. 1) My question is why i feel the pain between chest and shoulder. 2) How the get rid of anxiety of cardiac arrest. 3) What modifications i can do in my lift to keep my heart healthy.