What Causes Chest Discomfort Along With Pain In Arm?

Hi I am having cheast discomfort and left arm pain palpitations in heart and uper back pain. I did ECG Echo test holter for 24 hrs and some blood test all is normal... I am having hight acidity I don t know what going wrong with my heart and because of this i am getting anxiety as well... I am 22 years old and i am a smoker 20 sticks per day