Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain bad breath also known as Halitosis can occur due to a number of causes like poor oral hygiene, oral and dental infections, tonsil stones or tonsilloliths,post nasal drip, sinusitis, acid reflux,respiratory infections, diabetes etc.. As you have tonsils removed along with wisdom tooth extraction and sinus surgery certain causes gets eliminated but post nasal drip or phlegm buildup can be due to recurring sinus infection and needs evaluation.. You should consult an Oral Physician or an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations depending upon suspected cause can help in diagnosis.. Treatment of underlying cause will relieve the symptoms.. As of now you should start gargling with a flavoured mouthwash twice a day.. You should chew flavored sugarfree chewing gum.. Do warm saline gargles twice a day.. Limit the intake of high aroma foods like onion and garlic.. Drink plenty of water and maintain a good oral hygiene.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.