What Causes Sudden Pain In Joint Causing Difficulty To Walk?

I am a 56-year old female. One day I am feeling well and all of a sudden, the next day I am unable to raise my right arm. Within 24-hrs. it goes away without my doing anything. The next day it could be my inability to walk without a limp due to a painful left knee which can disappear within 24 or 48-hrs. Then suddenly, a joint in a hand swells and becomes painful and suddenly goes away. What could possibly cause such problems and what do you suggest I do?