Most of the local pain in the arm after pneumonia vaccination is caused by the local stimulation of the drug after the injection of the drug in the deltoid muscle of the arm. Most cases will gradually decrease or disappear completely after 2-3 days. If the local redness, swelling, heat and pain are more obvious and high fever is found, most of them are caused by infection at the local injection site, so it is necessary to go to the hospital for examination and make the correct treatment according to the specific situation.