If that tooth is RCT treated tooth than you need to redo it, or the prescription medicine need to change .

Hello, Please do take a second opinion with an another dentist and your OPG X-ray isn’t clear. Visit a dentist for thorough checkup. Medicines will temporarily relief you only! If swelling is present then do normal saline gargle otherwise warm saline gargle might help.

Hi... The OPG is not very clear...to see if the RCTs are fine or not but I can see a little bone loss between your incisors and laterals , the pain could be because of that pocket formation or it could be because of re-infection of any of the RCTs. Also since you haven’t mentioned which upper teeth it is difficult to address your problem. Consult the dentist again with your problem, also if you have any problem of food lodgement in that tooth let him know , explain your symptoms well.