My mum has both. Years ago they took a sample from a vein in her temple to test if she had polymyalgia as apparently this is the only way they can accurately diagnose it. If they want to do this to you I wouldn't recommend it as she often gets a sharp agonising pain there now.

While both are chronic pain disorders polymyalgia rheumatica is a form of rheumatic arthritis. My experience from having both is that polymyalgia responds very well to prednisone with long term remission from a six week course. I was diagnosed with poly long after fibro. My rheumatologist didn't seem to think there was a connection btwn the two.