The stuff I've read about arthritis says activity of the affected joints is better than inactivity -- this from the CDC, http://www.cdc.gov/arthritis/pa_overview.htm

As for arthritis preventing playing -- take a look at Keith Richards hands, http://www.ronankavanagh.ie/musicians-health/learning-from-keith-richards-fingers-why-musicians-get-sore/

See a doctor. Try to find an MD, therapist and/or guitar teacher familiar with arthritis and musicians. Get a diagnosis and a plan to keep playing if that's your desire.