Common side effects of the COVID-19 vaccine include: pain and swelling where you got the shot, fever, chills, tiredness, and/or headache. They should go away within a few days. If redness or tenderness persists over 24 hours, or your side effects are worrying, call your doctor.
Reduce pain and discomfort by: applying a clean, cool, wet washcloth over the area and use/exercise your arm. Reduce discomfort from fever: drink plenty of fluids and dress lightly.