The immune system works overtime to protect you from infection. According to, antibodies are a part of your immune system’s natural reaction to injury or infection. They help to eliminate the virus from your body. Loma Linda University Health. However, this response by the immune is what causes body aches in the first place.
At this point, your body also produces more white blood cells, which are a key part of our immune system — they help produce cytokines. Cytokines are small proteins produced in response to various stimuli, including infections, injuries, and inflammation, per the Cleveland Clinic. They are crucial in the body’s immune reaction to infection. However, the increased cytokine production triggers an inflammatory response and causes muscle and joint pain, which eventually leads to those dreaded body aches.