Might be sinus if its behind ur eyes u should mention this at ur next appointment or call doctors office and ask what u can do or what they can do
If its sinus you can take Actifed, Claritin, Benadryl, Sudafed.
I wake up with them too, it's sinuses from the swelling in your nose but I take hot shower or let the steam open up my sinuses. I found sleeping in the recliner helps little bit but it's not as comfy as my bed
Look into essential oils. You can mix a few drops with a little coconut oil and massage your temples and head with it.
I agree hot shower sounds good.. they may also be tension headaches ... you mentioned a stiff neck. If you have the time and money you should soooo go get a massage (: tension in the muscles in your neck can cause headaches. I would love to go get a neck and shoulder and head massage ! Of I could I would