The pain in the arm from the vaccination may be caused by the stimulation of the muscle nerves in the arm during the vaccination, but it may also be caused by the malabsorption of the vaccine by the muscles in the arm, which is usually a normal reaction after the vaccination and can usually be relieved by itself in 1-3 days. If the symptoms do not improve, the vaccination site should be contacted for further treatment. There are cases of adverse reactions to any vaccine, which are highly related to the individual’s constitution. The New Crown vaccine kills intracellular viruses by interfering with the binding of the virus to receptors in the body. Some people will have symptoms such as redness, swelling, hard nodes and pain at the vaccination site after vaccination, and they will feel pain in their arms all the time, and some people will have reactions with symptoms such as fever, weakness, nausea, headache and muscle aches, but usually the symptoms are mild, and this condition usually requires no special treatment, and they can recover on their own in 1-3 days by generally paying attention to rest and avoiding exertion. However, if the symptoms of adverse reactions after vaccination are more severe or last too long, such as a temperature of 39℃ or more or a fever lasting for more than 3 days, the possibility of secondary infection cannot be ruled out and should be registered at the injection site in time, reported to the doctor and treated accordingly. After injection of New Crown vaccine, avoid infection at the injection site and do not touch water to avoid local redness, swelling, heat and pain, which may cause increased pain in the arm.