Robin, my suggestion is to see a cardiologist. No doctor knows everything, some less than others.

I have this too in my left arm. The shoulder joint is ruined and necrotic from cortisone shots! Pain runs down to my elbow. I’m told that’s referred pain from the shoulder.

Have your doctor check for inflammation or tearing in your rotator cuffs. It’s common with RA.

It wouldn't hurt to have an MRI or CT Scan to see if the pain is caused by a herniated disc in your Cspine - that is what had been causing my pain for years - Check it out.

My shoulder pain, running down inside of my arm to the elbow turned out to be a complete rotator cuff tear in the right shoulder. Cortisone injections helped. Sadly, now I need shoulder replacement surgery.