What Is The Reason For Intermittent Pain In Jaw, Ear Fullness After Molar Was Removed?

Hi I had my upper right molar removed over three months ago and I keep getting sensititivty in the gum area and on and off pain in cheek and lower jaw which sometimes makes my ear feel full, it seems to flare up and down, my dentist said there is still a bit of bone fragment on the xray, even after to pieces of bone worked there way out, I am scared that maybe I have still an infection of some kind , the tooth I had pulled had earlier been root canalled and was failing. Before I had the extraction I had months of on off ear pain and a feeling of cold in my teeth on the side of this tooth.