Sorry but most likely removal of the wisdom tooth would solve the problem.
You can try to rinse your mouth in case there is food stuck in the area that might be causing the problem.
Best to contact a dentist to get a prescription and an examination to find out what is the best treatment for that wisdom tooth.
Great to hear. Did you ever find out what was causing it exactly?
If that is the case, the most important thing to do with that area is to maintain the hygiene and reduce the bacteria in that spot. You may need to go on a mouthrinse and get an interproximal brush or other dental instrument to help clean the area. It would be best to discuss this in particular with your dentist.
Hmm, at age 12, you almost have all your teeth coming out by now besides your wisdom teeth. The dentist would need to determine if its an extra tooth or if its a regular tooth but in the wrong place. You might need to go to an orthodontist to move it back in place or you may need to get it removed.