The long of it:

FMS (fibromyalgia syndrome) is a widespread musculoskeletal pain and fatigue disorder for which the cause is still unknown. Fibromyalgia means pain in the muscles, ligaments, and tendons – the soft fibrous tissues in the body.

Most patients with FMS say that they ache all over. Their muscles may feel like they have been pulled or overworked. Sometimes the muscles twitch and at other times they burn. More women than men are afflicted with FMS, and it shows up in people of all ages.

To help your family and friends relate to your condition, have them think back to the last time they had a bad flu. Every muscle in their body shouted out in pain. In addition, they felt devoid of energy as though someone had unplugged their power supply. While the severity of symptoms fluctuate from person to person, FMS may resemble a post-viral state.

Symptoms:

* Pain
*  Fatigue
* Sleep disorder
* Morning Stiffness
* Other Symptoms and Aggravating Factors

This is why it is so difficult to stick to an exercise regime, and why the walking challenge is such a big deal.
I do not need an alarm clock because I am woken up by pain every day of my life. And when I run around
and am very active that pain is amplified by a 1000.

Resources:
Fybromyalgia Network
Fybromyalgia Symptoms