1. Yes 2. See your doctor and get an x-ray. That will help diagnose arthritis, but for other types you also need a blood test as well 3. It depends on what type of Arthritis. I was diagnosis with arthritis in my 40s, but it was nothing to worry about, in my 50s it got worse after a forced hiatus from martial arts due to injury and in my case I will never kick over my head again.