Interesting — I was just writing on the topic of how emotions are connected physical pain, and I then come across this Scientific American blog post describing the physiological changes that explained the physical discomfort one feels when being dumped. The crux: your brain has evolved to use pain to dissuade you from behaviors that can damage you — like sticking your hand in a vat of flesh eating acid. This pain system is also fired off when you engage in social behaviors that go against the interest of your genes — like being dumped (which, isn’t usually your fault. Arguably, the pain is an incentive for you to not maintain the single status.)

Evolutionary biologists would say that it’s not surprising that our emotions have hijacked the pain system. As social creatures, mammals are dependent from birth upon others. We must forge and maintain relationships to survive and pass on our genes. Pain is a strong motivator; it is the primary way for our bodies tell us that something is wrong and needs to be fixed. Our intense aversion to pain causes us to instantly change behavior to ensure we don’t hurt anymore. Since the need to maintain social bonds is crucial to mammalian survival, experiencing pain when they are threatened is an adaptive way to prevent the potential danger of being alone.