Back pain is pain felt in the back that usually originates from the muscles, nerves, bones, joints or other structures in the spine.
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the pain-sensitive structures around the brain. Nine areas of the head and neck have these pain-sensitive structures, which are the cranium (the periosteum of the skull), muscles, nerves, arteries andveins, subcutaneous tissues, eyes, ears, sinuses and mucous membranes.
Arthritis is a form of joint disorder that involves inflammation of one or more joints. There are over 100 different forms of arthritis. The most common form,osteoarthritis (degenerative joint disease), is a result of trauma to the joint, infection of the joint, or age. Other arthritis forms are rheumatoid arthritis, psoriatic arthritis, and related autoimmune diseases. Septic arthritis is caused by joint infection.
Pain that has lasted longer than three to six months, though some theorists and researchers have placed the transition from acute to chronic pain at 12 months. Others apply acute to pain that lasts less than 30 days, chronic to pain of more than six months duration, and subacute to pain that lasts from one to six months. A popular alternative definition of chronic pain, involving no arbitrarily fixed durations is “pain that extends beyond the expected period of healing”.