system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Is there a biological/chemical explanation for the physical pain of Heartbreak?

More like explain like I've only had one semester of college chem and bio because I'm an engineering major.

Right now I have a physical pain in my chest and a difficulty breathing. Just because I've learned I'm not going to see a girl for a few weeks, which is objectively not a very big deal, I'm experiencing physical discomfort which outweighs my even my emotional response. What kind of biological processes are going on within my body? Why is there pain in the chest and gut specifically? What kind of signal has my brain sent to my body and why?

Thanks!
gpt
I don't know enough to go in to a ton of detail here, but it usually is some type of anxiety reaction. Anxiety often aggravates GI system. Stomach and heart share some nerves. So chest pain could be due to that (e.g. it is often for people to go to the ER thinking they are having a heart attack when they are just having heartburn/acid reflux). Also, anxiety can cause palpitations. This can cause "chest pain" and can also cause more anxiety which can start a cyclic reaction between anxiety-palpitations, etc.