A separated shoulder is an injury to the ligaments that hold your collarbone to your shoulder blade. In a mild separated shoulder, the ligaments may just be stretched. In severe injuries, ligaments may be completely ruptured.
In most people, a separated shoulder doesn't usually require surgery. Instead, conservative treatment — such as rest, ice and pain relievers — is often enough to relieve the pain. Most people regain full shoulder function within a few weeks after experiencing a separated shoulder.
Source: http://www.mayoclinic.com