The last couple of days, my right knee has been getting tighter and tighter... and, very painful... All of a sudden today, I can't straighten it out, and, could barely walk this a.m... and, there.s a lump, just below the inside (back) of my knee joint ... ALSO.. my right hand is acting the same way... I cannot straighten out my fingers!! I do have arthritis, but, I just had a shot of cortisone (about 10 days ago) for this... I'm wondering about the sudden onset of the knee thing... coinciding with my hand.... What do you think? Thank you.