Hi,Dear,Welcome with your query to HCM. Studied your query in full depth of its details.Reviewed it in context of your health concerns. Based On the facts, You mostly seem to suffer from- left maxillary sinusitis with intra-oral hard palate swelling with it.The MRI confirms this sinus infection.Seems that you have nasal obstruction for quite some time more than 2 yrs of your cheek swelling. This has lead to the nerve pains due to the periapical areas of the upper jaw teeths,which is increasing lately. Other causes of such a lump could be Maxillary sinus poly / adenocarcinoma/ or peri-apical abscesses with peri-apical radiolucencies/nasal obstructions with cellulitis of the maxillary bones. Intra-oral protrusion in the hard palate-gives lump in the mouth in your case. Treatment- -Treatment with Anti-histaminics +Anti-inflammatory +Antibiotics for 5-7 days is supplemented to recover the tissue edema prior to surgery . - Caldwell Luck Surgical Drainage or -Sos-Endoscopic nasal antrostomy making drainage of the pent up secretions in to nose or out anteriorly from maxillary sinusitis or Excision of the Polyp/ or adenocarcinoma of Maxillary sinus. This would fix the issue by proper treatment as planned above from expert ENT doctor CT and X-ray sinuses would help to plan the treatment in the best possible way. Hope that ,This reply would help you to plan further treatment soon with your treating doctors.Best of Luck and early recovery. Welcome any further query in this regard,which would be replied in next session. Good Day!! Dr.Savaskar M.N. Senior Surgical Specialist