So this was only discovered a few days ago. I eat everything on my left side, which is where I usually get my cavities. But, a few days ago, I would have an insanely cold sensation on one of my top back teeth. I thought it was because I was breathing in air which sometimes makes my teeth feel cold due to sensitive teeth. Though today, as I was doing jumping jacks in P.E. it really started to hurt. Then we had to run, and it was so bad, I had to power walk because everytime I landed to take another step, it jolt my head a tiny bit and hurt. I dont know what this is, maybe its a bad cavity? Or my feeling fell out from a previously filled cavity?