The dental pulp contains blood vessels, nerves, and connective tissue that help the tooth grow during its developmental stages. It is housed within a cavity that extends from the centre of the tooth, known as the pulp chamber, down to the tip of the root in the jawbone.
When this pulp becomes inflamed or infected due to decay, a crack in the tooth, or trauma, it can cause severe pain and, if left untreated, lead to an abscess or even systemic infection. It's important to speak to your dentist as soon as possible to radicate any longer term issues.