Hi. I ve had increased muscular/joint pain throughout the body, except elbows and spine. Also, great weakness, which was sudden rather than gradual. I ve had brain fog for a few years, and it seems to be worsening over time. Yet Monday, I had surgery to remove (superficial) skin melanoma, and all my muscular/pains had vanished when I woke up from general anesthesia. Would this indicate arthiritis?