Distal clavicle osteolysis is shoulder joint pain at the end of the collarbonethat is the result of bone disintegration and damage. The most common symptom is a sharp or aching pain at the junction of the acromioclavicular joint (AC joint) and collarbone. While the pain is usually felt during activity, there may also be a persistent tenderness around the joint during non-activity. Inflammation and swelling are also common manifestations.
Source: Verywell Health