system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When you’re sick and have a sore throat, what’s actually causing the soreness?
gpt
The cells on the surface of your throat dying, exposing nerves underneath that are not supposed to be exposed, and react by causing pain. 

When you have a cold or flu virus that causes a sore throat, the virus replicates by getting inside your own cells and causing your cells to produce more virus instead of doing whatever they were supposed to be doing. Once enough virus is made, the cell will break open and the new viruses will infect other cells nearby. 

In addition to that, your immune system is trying to get rid of the viruses and virus-infected cells. There's no way to do this without killing the infected cells. Your immune system recognizes which cells to kill because the cells display a sample of everything being produced at that moment inside of it, and if the sample of protein fragments being presented is not from your own body, it means it is from an invading pathogen.