I am glad to have you with us. Pain, discomfort covers a wide spectrum of pain or discomfort, (Subjective). Referring specifically to the question of arm pain during a heart attack , the emission spectrum of pain that radiates to the arm is wavelike and there is a variation in its intensity (sharp or dull).
I took care of a man once that had Left leg pain and he was having a heart attack so when in doubt, call you Dr. or seek treatment.
Again welcome to the forum.