I have continued to experience the symptoms that many others have described here including:
- intense / pulsating pain in neck and down into shoulders 
- significant challenges sleeping compounding the issue and resulting in little sleep or ineffective sleep
- lack of sufficient / effective sleep creating fatigue and exhaustion

Although I do not believe anxiety itself is the source, I experience increased anxiety due to concern and confusion related to the ongoing issue. Who would not be concerned about these symptoms? Of course they'd make you anxious.

I have a theory and the article below has inspired me to continue thinking about it and seeing if I am able to improve the situation by looking at it this way. 

Bottom line: I think I have adrenal fatigue or what is more commonly known as burnount. I did not want to admit this because I have a view of myself as some one who has significant capacity for working hard, dealing with challenges, etc. I know I have a always had a high threshold for working under pressure, long hours, an ability to focus and deliver large volumes of work. I take pride that I have worked in demanding roles where I managing through interpersonal conflict, complex problem solving, and required travel / geographic moves. All of these experiences have added to my life's richness, but I believe they are also creating these physical symptoms. 

Consider that I have turned to some of these habits (SEE IF YOU RECOGNIZE ANY FOR YOU) compounding the situation by placing additional adrenal demands and the crashes that follow including:
- Morning coffee and a second or third cup adding additional caffeine into the diet (sometimes just to get over the lack of effective sleep from the night before)
- Chocolate at night --- more caffeine, more adrenaline 
- Excessive exercise - - - more adrenaline
- Working harder during periods where I am feeling a bit of reprieve from the pain thinking "I better be productive to make up for that day where I was not able to be so productive at work" (often at night feeling energized and thinking, I will make use of this energy by doing some work tonight) 
- More frequent sex and and even masturbation extending the period before ejaculation which adds to the adrenal demands
- ALSO for many who have posted here an issue with exposure to chemicals, see the articles explanation that certain chemical exposures can stimulate adrenaline production 
- ALSO consider that the anxiety from not knowing what is going on and any small experiences of panic may create....yes, more adrenal production

Give the article a read and let me know any thoughts. Because of my self-concept as a high achiever, I hate to think "its burnout", but the explanation in the article made me consider it. I am VERY CURIOUS ABOUT YOUR TAKE ON THIS POSSIBILITY.