4) Joint stiffness
Stiffness is not the same as pain. Whereas pain is an unpleasant sensation associated with inflammation and tissue damage, stiffness is a very uncomfortable feeling that the affected joint is stuck in place. Joint stiffness is common in aging people and can be caused by various conditions, including arthritis, muscle strain, sports injuries, and trauma.
In rheumatoid arthritis, joint stiffness is more common in the morning or after long periods of inactivity. This is because the synovium (the lining of the joints) becomes inflamed and produces excess fluid. The fluid collects in the spaces between the joint bones when you’re not moving the joint. Stiffness may also occur when muscles and tendons become inflamed and are attached to the bone at the joint.