What is the enigma that is frozen shoulder? Frozen shoulder also known as 'Adhesive Capsulitis' is a spontaneous condition of the shoulder associated with pain and stiffness due to the contracture of the joint capsule. What Causes the shoulder to freeze? At present the cause of frozen shoulder is unknown. But there have been links made to our body secreting extra collagen type 2 fibres which in turn causes the soft tissues to contract around the Glenohumeral (Shoulder) joint