Can a virus trigger fibromayalgia or widesread chronic muscle pain?

Possibly: Widespread muscle pain is a feature of the flu, which is caused by a virus. There are a number lf "flu-like" syndromes caused by viruses, which may or may not include widespread muscle pain. Usually it does not become chronic. However, in unusualy cases, it can become chronic and therefore can be called fibromyalgia. However, fibromayalgia itself tends to be poorly understood, especially causes.