There are several possible reasons for the right lower tooth pain: 1, the tooth is suffering from dental caries, when the area of decay is large, the cavity will be very close to the pulp cavity, once people eat hot, cold, sour or sweet food, the stimulation will cause the tooth nerve to cause a transient pain, if there is food embedded in the cavity, it will also cause a particularly severe pain. 2, the right lower back tooth is suffering from pulpitis, the infection of the tooth tissue will cause pulpitis. Pulpitis is caused when the infection of the tooth tissue reaches the pulp. The most typical symptom of pulpitis is pain, usually severe, spontaneous pain or even nocturnal pain, and many patients with acute pulpitis have pain in the middle of the night that prevents them from sleeping. 3, pain in the right lower back tooth closest to the end of the tooth bed may be caused by wisdom tooth pericoronitis, a swelling and pain in the wisdom tooth area caused by infection of the soft tissues around the wisdom tooth. 4, chronic periapical infection or periodontitis resulting in .