According to clevelandclinic.com, the pulp inside your teeth is a soft substance full of nerves, tissues, and blood vessels. The pulp nerves are among the most sensitive nerves in your body. When these nerves become irritated or infected with bacteria (abscess), it can cause severe pain.       What are the possible causes of a toothache?       -tooth decay .   Tooth abscess (a bacterial infection inside the center of the tooth).   Tooth fracture (tooth fracture).   Damaged filling.   Repetitive motions, such as chewing gum, grinding or gnashing your teeth, these motions can damage your…