Tooth pain is a very common clinical manifestation, and there are many diseases that can cause tooth pain all the time. 1, the most common is pulpitis, which is an inflammation of the tooth pulp caused by bacteria entering the pulp. The pain is particularly severe when there is pulpitis, spontaneous pain, nocturnal pain, etc., and requires root canal therapy. 2. Chronic periapical infection can also cause toothache, and also requires root canal therapy. 3. If there is constant toothache, there may be a tumor in the jawbone that stimulates the root of the tooth, causing root inflammation that can lead to toothache, and requires removal of the tumor under the tooth.