Osteoarthritis: This is the most common cause of joint pain in multiple joints, especially in older adults. The wear and tear of the joint cartilage leads to pain, stiffness, and limited mobility in the affected joints.

Rheumatoid Arthritis: An autoimmune disorder that causes inflammation and pain in multiple joints, often including the hands, feet, hips, knees, and shoulders. It typically presents with symmetric joint involvement.
Fibromyalgia: A chronic condition characterized by widespread musculoskeletal pain, fatigue, and tender points. While it doesn't cause inflammation, it can cause significant pain and discomfort in various parts of the body, including the hips, knees, and shoulders.
Polymyalgia Rheumatica: An inflammatory condition that causes muscle pain and stiffness, primarily in the shoulders, hips, and knees. It's more common in older adults and can be associated with giant cell arteritis.

Septic Arthritis: A bacterial infection within a joint, which is a medical emergency. It can cause severe pain, swelling, and limited mobility in the affected joint. Prompt diagnosis and treatment are crucial to prevent joint destruction.
Lyme Disease: Caused by a tick-borne bacterium, Lyme disease can lead to arthritis, particularly in the knees, and can also affect other joints. Early recognition and treatment are essential to prevent long-term complications.
Gout: A form of inflammatory arthritis characterized by sudden, severe attacks of pain, swelling, redness, and tenderness in one or more joints, most often the big toe, but can also affect the hips, knees, and shoulders.

Psoriatic Arthritis: A type of arthritis that occurs in some people with psoriasis, causing joint pain, stiffness, and swelling. It can affect any joint, but most commonly affects the hands, feet, knees, and ankles.
Ankylosing Spondylitis: A chronic inflammatory disease that can cause pain and stiffness in the spine, hips, and other joints. It can lead to fusion of the spine and reduced mobility if not properly managed.
Sarcoidosis: A condition in which inflammatory cells (granulomas) form in various parts of the body, including the lungs, skin, and joints. Joint pain and arthritis can be part of the presentation, though it's less common.