Gums behind the back teeth should be swollen and painful according to different causes to take different treatments, common causes are gingivitis, wisdom teeth pericoronitis, odontogenic diseases, etc., commonly used treatments are medication, extraction, root canal treatment, etc.. 1. Gingivitis: Gingivitis will have symptoms such as bleeding, swelling and redness of the gums, which can be treated with periodontal scaling. 2. Wisdom tooth pericoronitis: Wisdom tooth pericoronitis can cause swelling, pain, redness and other symptoms, oral amoxicillin, metronidazole and other antibiotics for anti-inflammatory treatment, and if necessary, extraction surgery to remove wisdom teeth. 3. Dental diseases: dental caries, periapical periodontitis, pulpitis and other dental diseases may also cause gum swelling and pain, oral penicillin and other antibiotics for anti-inflammatory treatment, if the condition is serious need to take root canal treatment, extraction and other surgical treatments. All of the above medications should be used under a doctor’s supervision. Gum swelling and pain behind the back teeth may also be caused by other reasons, should go to the hospital in a timely manner, the doctor to identify the cause and targeted treatment. Medications should be used in accordance with the doctor’s instructions.