Paget's disease is a chronic bone disorder that causes abnormal bone remodeling, resulting in weakened, deformed bones. It occurs when the normal bone remodeling process shifts out of balance, causing new bone tissue to form improperly. Common symptoms include bone pain, fractures, and arthritis. Diagnosis involves x-rays, blood tests, and bone scans. Treatment focuses on controlling symptoms through medications like bisphosphonates or calcitonin, proper calcium intake, exercise if tolerated, and applying heat or cold for pain relief.