I feel a heaviness and dull ache in my left shoulder that sometimes feels like it goes into my left arm. Its been happening over the past week or so. It radiates to the top of my shoulder into just above my arm pit. Sometimes it goes up my neck to the bottom of my ear. Sometimes its not there at all. I also noticed today that I am experiencing heartburn. This worries me from what I have read. No major pain or anything other than what is described and I feel fine otherwise. What could this be?