Good suggestion, Ben. Completely relaxing the arm during an injection definitely helps and keeping the arm moving after the shot helps too. However, the very act of injecting the serum in the arm stretches the muscle fibers and triggers an immune response, leading to temporary inflammation and discomfort. Some shots can react with the body more than others such as the tetanus vaccination.

Those of us having a stem cell transplant require having all of our childhood, adolescents and adult vaccinations re-administered. I was having 9 vaccinations at a time over 2 arms. No matter how much I relaxed icepacks were my friends for the first couple hours. 😅. I know why babies are cranky after their vaccinations.