Introduction Shoulder pathology may be symptomatic or asymptomatic depending on the patient. We report the first case of a COVID-19 vaccination administration precipitating symptomatic calcific tendinitis from pre-existing, asymptomatic calcific tendinitis. Case presentation A 50-year-old Thai male began experiencing left shoulder pain about 3 hours following a COVID-19 vaccination. He waited at home for the pain to improve, and when it did not improve in about 3 days he decided to see a doctor at the orthopedics clinic. He was sent for ultrasonography of his shoulder, which revealed calcific tendinitis of the subscapularis tendon. Discussion A SIRVA is normally considered if post-vaccination shoulder pain has not improved within a few days following a vaccination in a patient without shoulder pain prior to the vaccination. In our patient, a COVID-19 vaccination precipitated asymptomatic calcific tendinitis to symptomatic calcific tendinitis. Conclusion Previously asymptomatic shoulder pathologies can be precipitated to symptomatic by a COVID-19 vaccination.