My husband suffers from breathing difficulties which come on suddenly any time day or night. During day he complains that his nose is blocked although there is nothing there when blowing his nose, this can last from half an hour to several hours. At night thiscomes on about an hour or so after going to bed, on waking his nose is blocked (nothing there when blowing nose) dry thoat as probably breathing through mouth, this lasts several hours before subsiding. All test done so far have been negative, but this is causing lack of sleep and tiredness, frustration, irritabilty during the day.