What is Fibromyalgia?
According to the National Institute of Health fibromyalgia is:
“A disorder that causes muscle pain and fatigue (feeling tired). People with fibromyalgia have 'tender points' on the body. Tender points are specific places on the neck, shoulders, back, hips, arms, and legs. These points hurt when pressure is put on them.” 
However the NIH is very unclear what causes fibromyalgia. Their Web site reads as follows
"The causes of fibromyalgia are unknown. There may be a number of factors involved. Fibromyalgia has been linked to:
- Stressful or traumatic events, such as car accidents
- Repetitive injuries
- Certain diseases"
The official criteria for classifying fibromyalgia is widespread pain for at least 3 months, and tenderness in at least 11 of 18 specific trigger points.  These trigger points are spread across the entire body. The problem is this criterion doesn't give any insight into the cause of fibromyalgia. It was never meant to. The criteria for fibromyalgia was originally intended for research purposes only. However the diagnosis quickly became used by physicians who lacked another diagnostic criteria for fibromyalgia. 
What makes things confusing is when other symptoms are included with fibromyalgia. According to Web MD "other fibromyalgia symptoms include:
- abdominal pain
- anxiety and depression
- chronic headaches
- difficulty maintaining sleep or light sleep
- dryness in mouth, nose, and eyes
- fatigue upon arising
- hypersensitivity to cold and/or heat
- inability to concentrate (called "fibro fog")
- irritable bowel syndrome
- numbness or tingling in the fingers and feet
- painful menstrual cramps
- stiffness 
A 2001 article from the Journal of Manipulative and Physiological Therapeutics, Fibromyalgia Syndrome: a New Paradigm for Differential Diagnosis and Treatment, states:
“It is our opinion that the original premise of FMS [fibromyalgia syndrome] as representing one grand, all-encompassing clinical syndrome is … an oversimplified classification scheme that lumps together several distinct conditions that all happen to share a common cluster of symptoms.” 
In other words, two different people can both have a diagnosis of fibromyalgia, yet their pain is caused by entirely different conditions.
The article goes on to classify fibromyalgia as either “classic fibromyalgia” or “pseudo fibromyalgia.”
Various Causes of Fibromyalgia
These people seem to have a pain perception problem. Generally they do not sleep well, feel fatigued upon waking, have low energy, can not tolerate heavy exercise and have a lowered pain threshold. There is often an associated clinical depression or anxiety disorder. Symptoms often first begin after a period of emotional stress or trauma and studies have shown that these people have decreased levels of serotonin.
Pseudo fibromyalgia describes people who have been misdiagnosed as having fibromyalgia when they have another cause for their widespread pain. Pseudo fibromyalgia has been broken down into three categories: organic diseases, functional disorders and musculoskeletal disorders.
Many other diseases such as hypothyroidism, inflammatory arthritis, anemia, Lyme disease, auto-immune disorders, multiple sclerosis and cancer can cause widespread pain. A diagnosis of fibromyalgia should only be given after these other causes of pain have been excluded. Many conditions in this category are also associated with fatigue, especially hypothyroidism.
Functional disorders are not true pathological conditions or diseases. These are things such as vitamin and mineral deficiencies, intestinal dysbiosis, dehydration and subtle hormonal imbalances. What these functional disorders have in common is that they can cause low energy and widespread pain.
The tender points of classic fibromyalgia are different than the trigger points from sore or overused muscles. Classic fibromyalgia is not a disorder of the muscles, but is a pain perception disorder. Pain from problems such as sore muscles, inter-vertebral disks, joints, herniated disks, or nerve impingement is not fibromyalgia.
WebMD.com states, “There are no scientific measures, such as laboratory tests or X-rays, that 'prove' you have fibromyalgia.” Therefore if a diagnosis can be made by x-ray or another test of joint or muscle function, is not fibromyalgia.
There are many symptoms associated with fibromyalgia, but labeling these as "symptoms of fibromyalgia" or "fibromyalgia syndrome," does nothing to explain their causes and is also very confusing.
Is fibromyalgia widespread pain and tenderness in 11 of 18 tender points, or is it a myriad of other associated symptoms?
Classifying fibromyalgia into different groups depending on cause is very helpful. Once this is done treatment can be focused on fixing the cause of fibromyalgia, instead of just suppressing the symptoms with drugs.
For more information on this there is an excellent article posted on dynamicchiropractic.com, Fibromyalgia Syndrome: Reclassification is Definitely Needed.
 What Is Fibromyalgia? Fast Facts: An Easy-to-Read Series of Publications for the Public. National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Fibromyalgia/fibromyalgia_ff.asp#a. Accessed March 7, 2010.
 Shomon, M. Living Well With Chronic Fatigue Syndrome and Fibromyalgia. New York: CarperCollins Books; 2004.
 Schneider M, Brady D. Fibromyalgia Syndrome: A New Paradigm for Differential Diagnosis and Treatment. Journal of Manipulative and Physiological Therapeutics. 2001;24(8):529-541.
 What Is Fibromyalgia?Webmd. http://www.webmd.com/fibromyalgia/guide/arthritis-fibromyalgia. Accessed March 7, 2010.
 Fibromyalgia Diagnosis and Misdiagnosis.Webmd. http://www.webmd.com/fibromyalgia/guide/fibromyalgia-diagnosis-and-misdiagnosis. Accessed March 7, 2010.