During the vaccination process, most people will feel varying degrees of pain. This is because the moment the needle pierces the skin, it will stimulate the nociceptive nerves in the skin causing pain. The pain level of this act is related to the individual’s physique, mental factors, injection method and technique, etc. Most people can still tolerate the pain level of vaccination.1. Individual physique: If the recipient has a high pain threshold, he or she may not feel pain or the pain is very mild. If the pain threshold is low, the recipient is more sensitive to pain and will feel very painful; 2. Mental factors: If the recipient is nervous and fearful during the vaccination process, he or she will easily feel severe pain; 3. Injection method and technique: If a finer needle is used for the injection, the pain will be reduced, and if the needle is thicker, the pain will be heavier. In addition, if the nurse pushes the medicine too fast, it is easy to cause more obvious pain, and if pushed slowly, the pain will be reduced. In addition to feeling pain during vaccination, some people may also experience pain at the injection site after vaccination, and there are individual differences in the severity of pain. If there are no abnormal local manifestations, there may be transient, mild pain that can be relieved on its own without special treatment. If there is local redness, swelling, hard nodules, and itching, the pain may be more pronounced and last longer, and in severe cases, the entire upper limb may be painful, or even unable to be lifted, resulting in restricted movement. In this case, if the symptoms gradually decrease, you can continue to observe and do not need to take special treatment. However, if it gradually worsens, you need to go to the hospital and follow the medical advice to take treatment measures.