All emotions are energy. Unexpressed emotions are stored in the emotional body. The whole purpose of your spiritual path is to let go of these emotions and move away from the emotional body. It is the emotional body that the Self hangs on to, holding on to the emotions of fear, doubt, jealousy, anger, greed, etc. These emotions are carried over from many incarnations and have never been dealt with. They stay in the soul memory, eventually coming out into the mental (thinking, thoughts) memory, waiting to be dealt with.
The emotional body is a part of humanity tied to the animal part of you. It is a part of the Self, a separate body, once designed to protect you, now keeps you from moving forward. The emotional body knows all of your fear, anger, frustration, and it is capable of pulling those negative emotions out of a hat, like magic, whenever it needs to slow you down.