I feel deep in my throat deep down from right tonsil canker sore. it s pain when i swallow hard food from this side. i took arcoxia nsaid before due to back pain.is it related? causes? treatment? need to take vitamins?

Yes, canker sore (aphthous ulcer) can be an adverse effect of arcoxia (a COX-2 inhibitor). You can use local anesthetic gel (teething gel for kid) before eating for less pain. Vitamins have no role in treatment of canker sore.

You don't need pills. You need a diagnosis. Please see your General Practitioner or an ENT specialist for examination, accurate diagnosis, appropriate treatment plan. Please stop trying to practice medicine without a degree. See a physician.