sinuses get stuffed up every time i lie down

[linonline]

For most of my life every time i go to sleep my sinuses fill up and then in the morning i have a headache in my forehead and back of my head and back of my neck.  I now use a sleep apnea machine and it helps but when my sinuses get full and blocked i still wake up with a headache.  It feels like my whole head is full of mucus.  All doctors ever give me is nasal spray and far as i can see it only makes it worse.  It takes several hours every morning to unblock my sinuses and get rid of the headache. I have also used a humidifier and that doesnt help. I need some help and so far not getting any.