The left side of the tooth pain left head swelling and pain to consider with acute pulpitis, wisdom teeth pericoronitis and so on. 1. Acute pulpitis: common in caries, severe periodontal disease or oral trauma, resulting in pulp infection, severe paroxysmal pain, especially at night pain is worse, the left side of the dental nerve inflammation tooth pain at the same time can be dispersed to the same side of the head, causing headaches, at this time the need to carry out root canal treatment. 2. Wisdom tooth pericoronitis: If the left wisdom tooth has not erupted, the nearby gums can be caused by food residue retention, bacteria, calculus and other stimuli causing inflammation, resulting in gum swelling and pain. Inflammation spread to the nerves or surrounding tissues, can cause head pain on the same side of the head, such cases can be treated with anti-infection. The left side of the tooth pain left head swelling and pain may also be related to other causes, it is recommended to consult a doctor in time to clarify the cause of the disease, under the guidance of the doctor standardized treatment.