The following is the definition of Fibromyalgia on the DWP site.
A condition, which affects the muscles and ligaments but does not damage the joints. It is a common condition and can be severe. In fibromyalgia the fibrous tissues (fibro-) and muscles (-my) are affected by pain (-algia) and tenderness. Fatigue is often the most severe aspect of fibromyalgia
Given the statement "that it does not damage the joints" it would suggest it is not considered to be linked to arthritis.
My wife suffers from both and says she can distinguish the pain from one versus the other.
Stephen