Engorgement is the swelling or congestion of body tissues. When we are referring to breast engorgement, we are describing the painful swelling that occurs when the breasts become  very full and very firm.  Sometimes the breasts are actually hard and all these sensations lead to very painful breasts.  They can feel very heavy, sometimes throbbing, you noticed your skin is quite stretched and sometimes this fullness and firmness leads to your armpits.  Engorgement can affect one or both breasts.