Emotional Imprisonment

it is a very common stereotype that women are emotional and men are cold, emotionless.

Though cant be sure since im not a girl, I believe that men experience the same amount of emotions as a woman does. However, much of it is brushed off or left unexpressed.  It is the culture that society through the generations imposed on us to be strong... the stronger sex... so that someone would still be standing when the women break down in an emotional event. It is ladylike for a woman to be emotional; for a guy, its uncool. 
Slowly, as we grow up, with this culture and expectations being ingrained, we grow a hardened shell around our heart, so that the emotions stay within and dont come out.

it is not that men are or really want to be emotionless. They are  afraid that their ourbursts of emotion would be met with spoken or unspoken responses of 'man up' or 'grow a pair'.