Hi. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain swelling of the Parotid Gland especially when you eat is not due to infection of the parotid gland but it is due to clogging of the duct of the salivary gland which can be due to obstruction of the duct orifice by some foreign body or it can be due to formation of crystalline stones in the gland or the duct from the minerals present in saliva and can lead to clogged duct and when the saliva cannot flow to mouth from the gland due to obstruction it flows back into the gland and there is swelling in the gland and due to expansion and stretching of the gland there can be pain.. During eating there is increase in the flow of saliva and due to it the swelling also increases during meals.. I would suggest you to consult an Oral Physician and get evaluated and in case if salivary stones is diagnosed the doctor can advise you an Endoscopy [SIALOSCOPY] to rule out the location of the stones..In case of superficial stones the physician can palpate over the stones and remove them manually by pushing towards the ducts.. In case of deeper stones surgical removal has to be done.. As of now you can take more of sour candies, lemon drops or sugar free chewing gums as they will stimulate saliva flow and at times the stones gets flushed out with the saliva.. Hope this information helps.. If you find the answer helpful please give me a Five Star Review and click on found the answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..