How does the pain of fibromyalgia originate. Could you define how does the pain feel like? Is it a pain in flesh around joints or what?

Variable. The pain from fibromyalgia originates from hypersensitivity in your nervous system. This hypersensitivity comes about from the wrong physical and emotional stressors in the wrong person at the wrong time. When you system becomes overwhelmed, neural changes happen that cause the sensitivity. The pain is usually aching to sharp and located in the muscles and joints.
Widespread. The pain of fibromyalgia is chronic, widespread pain the is muscular in origin. Additionally there are trigger points that are tendered to palpation. This appears to be from over active nerves connected to the muscles.
Most curious. Description of #fibromyalgia (fm) pain best answered by someone with fm. I suspect similarity to aching muscles most adults have had lasting for several days as "pain in the neck"; in fm this type pain within all 4 quadrants of back. Central sensitization is fashionable theoretical model with some possible data. There is also clinical data for true ongoing peripheral soft tissue pain generation.