A stiff-feeling joint is not caused by weakness or reluctance to move the joint due to pain.
Some people with stiffness are capable of moving the joint through its full range of motion, but this movement can require extra force.
Joint stiffness caused by inflammation usually occurs or is worse immediately after awakening or after prolonged resting or immobility. Stiffness is common with arthritis. Morning stiffness commonly occurs with rheumatoid arthritis Rheumatoid Arthritis (RA) Rheumatoid arthritis is an inflammatory arthritis in which joints, usually including those of the hands and feet, are inflamed, resulting in swelling, pain, and often destruction of joints.... read more 
and other types of inflammatory arthritis and gradually lessens with activity after an hour or longer. Stiffness that gets worse as the day progresses is usually not caused by inflammation.
Doctors can sometimes diagnose the cause of stiffness by the person's other symptoms and the results of a physical examination. For example, different types of arthritis may affect different joints. How long stiffness lasts can also be a clue. For example, if stiffness lasts for less than 15 minutes, the joint is probably not inflamed. The person is examined to make sure that the problem is not due to pain with motion or weakness. Doctors examine the muscles as well as the joints to make sure that the problem is not muscle rigidity as occurs in Parkinson disease Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more or muscle spasticity that occurs in strokes Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction) and symptoms that... read more and spinal cord disorders Overview of Spinal Cord Disorders Spinal cord disorders can cause permanent severe problems, such as paralysis or impaired bladder and bowel control ( urinary incontinence and fecal incontinence). Sometimes these problems can... read more . Because inflammatory arthritis is often the cause of joint stiffness, blood tests (for example, to look for levels of rheumatoid factor) and x-rays or ultrasonography may be done.
Stiffness is relieved by treating the disorder causing it. Stretching, physical therapy Physical Therapy (PT) Physical therapy, a component of rehabilitation, involves exercising and manipulating the body with an emphasis on the back, upper arms, and legs. It can improve joint and muscle function, helping... read more , and taking a hot shower after waking may relieve stiffness and improve the ability to do activities.
