Has anyone heard of polymatica rheumatica as compared to fibromyalgia?

I have and from my limited understanding know that one is able to be conclusively diagnosed as an inflammation issue where as the latter is much more challenging to pinpoint a source.....perhaps a nerve issue.
From the Mayo Clinic:
"Polymyalgia rheumatica is an inflammatory disorder that causes muscle pain and stiffness, primarily in your neck, shoulders, upper arms, hips and thighs; where as fibromyalgia is a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues. Researchers believe that fibromyalgia amplifies painful sensations by affecting the way your brain processes pain signals. "