Other contributors have probably already given the best answers, but it's interesting that Sqad refers to causes possibly being 'emotional ..........' It seems to me that many problems that can't otherwise be explained are put down to emotional factors, stress, etc. and I'm a bit suspicious about that. It might be worth trying something called OLBAS, an inhalant/decongestant. A web search will produce much to read about this product and how to use it. Best wishes.