system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 why does some pain make us nauseous?

Just like the title. I’ve had all sorts of pain in my life and most I can handle. But at the moment I’ve got back pain that is making me nauseated and I don’t understand why.
gpt
If you are in intense pain and your nervous system is in a hyperactive state, while hormones are changing your basic system responses — BP, HR, etc. — it leads to a feeling of nausea. Your brain just has too much going on to process things accurately. Your body is trying to protect itself.