Question

a person who complains of pain and stiffness that becomes worse after sitting for a prolonged time may have​

Answer 1

I believe that the answer would be arthritis, people are commonly and most likely suffering from arthritis.

Answer 2

Seems like arthritis. (Inflammation of the joints.) One of the most common symptoms of arthritis is stiffness and/or pain when waking up in the morning, or after prolonged periods of inactivity.