I get joint and muscle pain. I have a family history of arthritis (ankylosing spondylitis, osteoarthritis, septic arthritis, the works) on both my mum and dad's sides of the family. My nana complains of non-specific ailments and fatigue, as does my aunt (her daughter), and my aunt, at least, fulfils the ICC criteria for ME (but also has septic arthritis and osteoarthritis, and may have AS too).
I, too, had scans for types of arthritis (MRI to check spine, X-ray to check wrists and hands), but nothing showed up.
I think infection and immunity may pay a part. As my immune system has got better somewhat (nine months of both LDN and Imunovir), the joint pain has mostly gone, leaving just muscle and neuropathic pain. I also notice the numbness and tingling more, but I suspect that's because the joint pain has subsided.
Occasionally, I wake up with a burning, fizzing pain in my joints, which feels more gout-like.