Fibromyalgia is a reasonably common diagnosis.  A few interesting links.

A very good review in American Family Physician .. with a patient handout

POEM on fibromyalgia

Like many (?most?) physicians .. I struggle with this diagnosis.   Treatment is only occasionally successful, and it seems that once the dagnosis is made, depression and anxiety worsen.

So I'm not very enthusiastic about making the diagnosis.  There is no test for it .. no "wonder drug" that will treat it …

There are also an alternative view of this condition:

Based on precedents in the literature, I could assert even 15 years ago that the "fibrositis/fibromyalgia" construct was a sophism that would serve no therapeutic purpose. Even then, my conviction was readily defensible. Today, as I've detailed most recently in the 2nd Edition of Occupational Musculoskeletal Disorders, the construct itself is not defensible on scientific grounds. It is a but one of a number of labels that grows out of an iatrogenic diagnostic process and that denotes escalating discordance between feeling miserable and possessing no demonstrable primary pathophysiology. Today I am joined by others who share my disdain for the labels and the labeling.

He's kinda got a point. 

Or does he? 

When humans are in pain … especially when they don't know the reason … depression, fear, despair and anxiety are paramount.  We YEARN for a diagnosis.  A REASON .. something to explain the symptoms. 

So does it really matter that we can't do a test for this disorder?  So long as there is a reasonably clear set of criteria .. and a better-than-nothing treatment strategy .. at least this diagnosis provides a sense of clarity.