they don't like to remove tonsils as routinely as they used to.You don't say that your symptoms are accompanied by a sore throat so maybe you suffer from catarrh.If you smoke it would help to give up.In some cases it also helps to reduce consumption of dairy products.
An ex-partner of mine suffered a similar problem for several years, and despite repeated visits to the doctors was unable to obtain any satisfactory treatment. Eventually the problem appeared to go away of its own accord.