Could The Pain In The Upper Left Arm Related To Heart Or Could It Be A Muscle Or Bone Issue?

I'm having pain in my upper left arm for the last 24 hours or so. It's mostly in the joint of my shoulder, but seems to radiate down toward my elbow. I do not have any chest pain or tightening. I'm not having any difficulty breathing. I'm concerned because this isn't the first time I've had this pain, but this is the longest it's lasted and the worst it's felt. I took 2 Aleeve around 3pm this afternoon with no relief. The pain is just as great, if not a little worse so I took 2 Advil around 8pm. It's nearly 9pm now and the pain is not subsiding. I've always slept on my left with my arm extended under my pillow. So, part of me wants to think it's a muscle or bone issue - but the other part of me doesn't want to ignore the possibility of a heart issue. Any suggestions are most appreciated.