I am a registered nurse recovering from rotator cuff surgery (June, 2017) from a flu vaccine I received last October 2016. SIRVA - Shoulder injury related to vaccine administration. If a vaccine is injected wrong it could cause bursitis, brachial neuritis, shoulder tendonitis, Impingement Syndrome, rotator cuff Tears, and Adhesive capsulitis (AKA Frozen Shoulder). there is a knowledge deficit in the medical community and few orthopedics have awareness. Hope this helps.