I just wanted to update the conversation I had recently regarding a very confusing set of symptoms and many thanks to all who responded. I am pleased to report that all is well. My stiff neck and strange headache have improved dramatically and I can only assume my shoulder impingement was the culprit.
I have had my second Rituximab infusion prior to which I had dreadful neuropathy in my hands. I am noticing a steady and continuing improvement with that and much less joint pain. I didn't suffer as a result of accidentally taking too much Prednisone. I took 25mg instead of 15mg so I dropped back 5mg for the next two nights and then 1 mg a night to get back to 10 mg. My PMR symptoms are also better.
I have no idea what happened or why I had what I had but I am hopeful I can now begin the slow taper so we'll see how it all goes.
Thanks again for all the concern and input.