interesting research from SfN conference
Functional magnetic resonance imaging (FMRI) from subjects going trough a painful break-up (social pain) show a surprising similarity to those from subjects experiencing physical pain. These results suggest that the two painful experiences are mediated by the same nervous circuits.

Some ambitious scientists decided to investigate the interaction between the two. They selected subjects in long term relationships and they observed that the response to physical pain was significantly reduced while they were holding hands with their beloved partner. However, the same effect does not occur when single subjects were holding hands with a stranger. Conversely, they reported that pain killers can attenuate feelings of rejection and isolation in healthy patients. Conclusion: love (or rather the lack of it) hurts.

(NOTE: paracetamol is not intended as a replacement for romantic relationships)