Most probably its pericoronitis. Keep the area clean and start luke warm saline rinse after your meal to keep the area clean. Visit dentist for further assesment.

Pain in wisdom teeth at your age usually happens during  the eruption of wisdom tooth i.e. the process by which it comes out of the bone into your mouth. The problem associated with it usually is Pericoronitis i.e. inflammation of gums around the wisdom tooth. You should see a dentist to ascertain how severe the problem is. Depending upon the severity (of how it looks inside your mouth to the experienced dentist, does not depend on how severe you feel it is), the treatment might vary from as simple as keeping that area clean, to the need for removal of the tooth in question. As the pain is on biting, the problem might be with some other tooth also. It is sometimes difficult for a normal human being to figure out which exact tooth is hurting. So you should consult a good dentist as soon as possible, or it might worsen