Why causes my shoulder blade to stick out?

A variety of causes: Your condition is called scapular winging and usually affects only one side. Causes include injury to one of the nerves called the long thoracic nerve if you had an injury. Parsonage turner syndrome is a viral syndrome that can affect the brachial plexus and cause scapular winging. This is a self limited condition and can take upto 1 year to resolve. A condition called sick scapular syndrome can cause both scapulas to wing. Treatment is usually with physical therapy. See a shoulder specialist to really find out what the cause is.