Adhesive capsulitis, also known as frozen shoulder, is a condition characterized by inflammation and stiffness of the shoulder capsule that greatly restricts movement and causes pain. It typically affects those aged 40-60 and more commonly in females. Symptoms include gradual onset of pain and stiffness, especially in external rotation, internal rotation, and abduction. While the exact cause is unknown, it is self-limiting and usually resolves within 18 months with conservative treatments like analgesics, physiotherapy, corticosteroid injections, and manipulation under anesthesia.