Edward Smith, a psychologist at Columbia University says that the pain of rejection does indeed hurt. Using brain scans from 40 volunteers, Smith discovered that intense emotional pain activates the same neural pathways as physical pain.
Each of the volunteers had suffered a surprise breakup, having been rejected by their significant other. The researchers put the study participants through a fMRI scanner, asking them to rate their pain performing four tasks.
In the rejection portion, they were asked to rate how much they hurt when viewing a picture of their ex and a picture of a good friend with whom they had had good experiences. The participants then rated their pain during physical stimuli — one stimulus simulated the heat from holding a hot cup of coffee, while the other was a warm probe that was less painful.