By Sandee LaMotte

CNN

(CNN) -- Do you ache all over? Do you find yourself exhausted even after a full night's sleep? Does just the slightest touch on certain spots on your body make you want to scream in pain?

You could have fibromyalgia, a painful musculoskeletal disease characterized by widespread muscle pain, oversensitivity to common pain, extreme fatigue and sleep, mood and memory problems.

What is fibromyalgia?

Fibromyalgia's name comes from "fibro" (the Latin term for fibrous tissue), "myo" (the Greek word for muscle) and "algia" (the Greek word for pain). According to the National Fibromyalgia Association, an estimated 3% to 6% of the world's population suffers from the condition: about 450 million people, including at least 10 million in the United States.

Fibromyalgia is considered a rheumatic disease like arthritis because it impairs joints and soft fibrous tissues like muscles, ligaments and tendons. But fibromyalgia is not a true form of arthritis, as it doesn't cause damage to those muscles and joints.

Instead, the disease wreaks havoc with the body's pain centers, causing muscle stiffness and pain, intense fatigue, difficulty sleeping, migraines and terrible memory and concentration issues, often known as "fibro-fog."

What's fibromyalgia feel like?

Those who struggle with fibromyalgia say the muscle and tissue pain can include a deep, achy misery, an unbearable throbbing or stabbing, or an intense burning sensation. Often, the pain occurs in muscle nodules, or myofascial trigger points, causing restricted movement and full-body agony.

"I used to say it was like a blowtorch," said Lynne Matallana, co-founder of the National Fibromyalgia Association. She began the advocacy group in 1997 after years of suffering from chronic pain.

"The pain radiates out so much that your skin, your hair, your nails, everything hurts. Anything that touches you hurts you. You can't wear jewelry; you can't wear anything with a collar or rough texture. I used to put pillows at the bottom of my bed so the sheets wouldn't touch my legs."

Overwhelming fatigue is another classic symptom. Between the pain and the exhaustion, says Matallana, she often felt despair.

"You feel like you can't move, you can't think, and time seems to last forever and ever," she explained. "You lose sense of the fact that you could be better."

Fibromyalgia suffers often have sleep issues, such as restless leg syndrome, and struggle with frequent sleep disruptions. The National Sleep Foundation calls the connection a "double-edged sword: the pain makes sleep more difficult and sleep deprivation exacerbates pain."

Because both pain and exhaustion are invisible, it's often hard for anyone with fibromyalgia to convince family and friends of the extent of their misery. To make matters worse, it wasn't long ago that many doctors thought fibromyalgia was psychosomatic. Sad stories of going from doctor to doctor only to be told that the pain and fatigue are "all in your head" are common among patients; as are stories of losing marriages, relatives and friends who could not understand the debilitation that the disease can cause.

"Doctors didn't accept it; patients didn't know what was wrong with them," Matallana said, describing what having fibromyalgia was like a decade or so ago. "Everyone felt so hopeless. I did a lot of suicide prevention counseling in the beginning of my work with the foundation.

"I always believed that if you went to a health care provider, they would have an answer for you. I didn't realize there are things they just didn't understand," she added, explaining that many doctors wanted to help but didn't know how.

"What I would often hear is, 'We don't believe it's being caused by anything other than stress or whatever. You need to change your lifestyle.' " It was like they were saying, "I don't know what to do to help you, so go do this, so I can take care of a patient I know how to help."

"So I quit work, I stayed at home, I tried to exercise and reduce stress," Matallana said, "but we didn't know enough about how to put those actions into a workable plan that would slowly help me get better."

What causes fibromyalgia?

Fibro can strike at any time. Symptoms often begin after a traumatic physical event, such as a car accident, surgery, even infection. Flu viruses, herpes simplex, the Epstein-Barr virus and hepatitis B and C may contribute to the onset of fibromyalgia.

Psychological or emotional stress such as abuse, the loss of a parent or going to war can also trigger the disease. A recent study in Finland found that being exposed to family trauma such as alcohol and financial problems, chronic illness and depression or divorce while growing up was associated with a diagnosis of fibromyalgia later in life.

There's even a link between sleep disorders and fibromyalgia. A study in Norway found that women older than 45 with frequent sleep issues had five times the risk of developing fibromyalgia than sound sleepers.

The National Institutes of Health says that between 80% and 90% of those diagnosed with the disease are women, but no one really understands why.

One theory is that lower levels of serotonin, a brain transmitter that helps regulate pain, may contribute to the development of fibromyalgia. Men make more serotonin than women, which some feel could explain the gender gap.

Another theory links female hormones and menopause to the disorder, but both of these are unproved.

If you have other arthritis-related conditions such as rheumatoid arthritis, osteoarthritis or lupus, your risk of getting fibromyalgia is higher. There's also a familial connection, so if your mother has fibromyalgia, you're more likely to contract the disease.

Other conditions such as irritable bowel syndrome, painful bladder syndrome, anxiety, depression and temporomandibular joint disorder (or TMJ) often go hand in hand with fibromyalgia, as do several sleep disorders such as restless leg syndrome and sleep apnea.

Today, researchers believe that the bombardment of nerve pain that occurs in fibromyalgia may even alter the brain. Some feel that alteration could be related to abnormal levels of certain chemicals in the brain (like serotonin), or perhaps how blood flows through the brain. A study last year found that spinal fluid and plasma from people with fibromyalgia contained significantly higher levels of inflammatory chemicals, which could trigger swelling and pain.

Scientists are also looking into the link between damaged peripheral nerves -- the small nerves of the body outside the brain and spinal cord -- and the chronic pain of fibromyalgia. One study found "withered or sparse nerve endings" in people with fibromyalgia, and two others found "small-fiber" nerve damage in those with the disease.

Regardless of the cause, the result is that the central nervous system alters the way it processes pain messages throughout the body. Then, the theory goes, the pain receptors in the body develop a type of "pain memory," making them oversensitive and over-reactive to any degree of pain.

"As time went on, I also described the pain as a sort of poison or acid going through my veins," Matallana said. "It is almost like you are slowly being drained of anything in you that would give you the strength to get better and help the pain go away."

How do I know if I have fibromyalgia?

It can take a long time to get a diagnosis for fibromyalgia. There is no test. You can't tell from an X-ray or blood test. Your doctor must consider the entire group of symptoms: pain, fatigue, sleep disturbances, cognitive dysfunction, mood disturbances, tenderness, stiffness and functional impairment.

Because myriad other conditions share symptoms, doctors often need to rule out other diseases before a diagnosis of fibromyalgia can occur. You will probably be screened for neurological disorders such as multiple sclerosis and myasthenia gravis, an autoimmune disease that leads to muscle weakness, as well as depression and anxiety.

A blood test called FM/a can help distinguish fibromyalgia from other rheumatic diseases like Sjogren's syndrome, rheumatoid arthritis and lupus. A complete blood count will help rule out thyroid disorders, anemia and vitamin deficiencies that can cause fatigue and sleep problems.

For many years, fibromyalgia was diagnosed by pressing firmly on 18 typical trigger points or small patches of tightly contracted muscle tissue. If 11 or more of those trigger points were painful, the person had fibromyalgia.

That's no longer recommended. Tender spots come and go, and doctors were unsure of how hard to press. You may still experience a test like that, but since 2010, it's no longer the gold standard for diagnosis.

The American College of Rheumatology now says that a diagnosis of fibromyalgia will be given if pain has lasted more than three months, with no other underlying medical condition, and is widespread, which means it must occur on both sides of the body and above and below the waist.

Because of the many challenges in diagnosing fibromyalgia, finding a doctor with experience in separating it from other diseases is key. An experienced rheumatologist -- a doctor who specializes in musculoskeletal and autoimmune disorders -- will be the most successful at diagnosing fibromyalgia.

How is fibromyalgia treated?

Widespread pain is often treated with over-the-counter pain relievers, but narcotics are not recommended, as they can increase pain over time.

In 2004, the US Food and Drug Administration approved the first drug for fibromyalgia. Pregabalin appears to work by calming overactive nerves. Unfortunately, it has two significant side effects, dizziness and sleepiness, that might dissipate over time.

The agency has since approved two more drugs: duloxetine is approved for anxiety, depression and neuropathic nerve pain; milnacipran is another antidepressant approved for fibromyalgia.

While those drugs can help some with the disease, many find little relief from medication.

Patients are encouraged to turn to physical and occupational therapy to improve muscle strength and flexibility. Stress can also be lowered via yoga, tai chi, meditation and counseling. Massage can be helpful, as it relaxes muscles, reduces stress and improves range of motion in muscles and joints.

Science has joined in the search for alternative treatments: the National Institute of Arthritis and Musculoskeletal and Skin Diseases has a number of studies underway into the roles of exercise, behavioral therapy and sleep interventions.

"We now know that pain can be learned," Matallana said. "A lot of us with a genetic predisposition, we were trying to do it all, and we wore ourselves down. We didn't eat well, didn't exercise, didn't meditate and take time for ourselves. We overstressed the whole system.

"Fibromyalgia is when you have pushed your system beyond the point it can function, and like a computer, sometimes you have to reboot."