The booster shot generally refers to the new crown vaccine booster shot, the new crown vaccine booster shot after arm pain with hard lumps, generally considered to push the speed of the drug too fast, the adverse reaction of the drug due to. 1. Push the speed of the drug too fast: physicians in the vaccination of the new crown vaccine, due to push the speed of the drug too fast can cause the drug is not well absorbed, thus causing the occurrence of this situation. 2. Adverse drug reactions: for those who are vaccinated, each person’s physique is different, due to the existence of individual differences in factors, vaccination can cause some adverse reactions to those who are vaccinated. Arm pain with hard lumps, need to go to the hospital by the physician to deal with, they can not randomly use drugs.