It hurts love hurts my eyes ... and the "seal" of scientists. According to research, culpable for the pain we cause separation or separation loved one is oxytocin or else the "love hormone."
This is the hormone that "binds" the mothers with their babies , their sexual partners among themselves and generally is the chemical cause of social ties and eventually love.
As established in the investigations, which made scientists Feinberg School of Medicine of Northwestern University in Chicago, the hormone responsible for fear and separation anxiety especially for the pain of love.
One of the functions of oxytocin is to enhance social memories in a specific region of the brain. When an experience is painful mentally and physically, this hormone activates a part of the brain that intensifies her memory.
In other words is the same hormone that creates the feeling of happiness when we love. The memory of love becomes painful after the end of a relationship and so ... poname!