I am 83 years old and for about a year now, I have stiffness in my rib cage. When I get up or sit down or bend over, all my ribs hurt and it seems to radiate from my spine around the ribs. My neck is also stiff and painfl. A few months ago, for the first time in my life, I had pneumonia in my left lung, spent 5 days in the hospital, developed A-fib. What may be causing the rib pain other than arthritis? I m sure I have arthritis.