Generally, after receiving the New Crown vaccine, some patients may experience muscle soreness due to individual differences and the inherent characteristics of the New Crown vaccine itself, for the following reasons: 1. The New Crown vaccine contains some components that stimulate muscles and nerves, and some patients may experience arm muscle soreness, injection site pain, fever and other symptoms as a result; 2. There exists a substance in our skin, muscles and other tissues called antigen-presenting cells, which, when they detect foreign invading components, trigger a chain reaction and then form antibodies to protect against specific pathogens, which is also known as an adaptive immune response. In the course of the reaction, blood vessels may dilate and nerves in the arm may be stimulated as a result, causing pain. 3. For some patients with muscle soreness as well as heavy redness and swelling reactions, this may also be caused by inflammation of nearby lymph nodes or lymph vessels. Normally, this muscle soreness that occurs after vaccination with the new crown vaccine will subside within 2-7 days. However, if a patient has an adverse reaction such as secondary infection or aseptic abscess after vaccination, it may lead to persistent increase in local redness, swelling, heat and pain, obvious enlargement of local lymph nodes, muscle soreness to the point of not being able to lift the arm, etc. In this case, it is necessary to seek medical treatment in time to avoid serious discomfort.