Tooth is a hard structure made up of enamel, it has to come out piercing the covering gum tissue and skin above it. In the process of emerging, it is replacing the tissue on all sides surrounding it and making a space for itself and that is causing pain. This pain and discomfort is true for all teeth, not just wisdom tooth. When babies teeth, they are cranky due to discomfort and cry. Just ask any parent! However, sometimes wisdom tooth are impacted; that means they re closer to nearby molars and that causes additional pain.