Yes I was a hairdresser so it involved a lot of looking down, had done it for 10 years.
The headaches that are relived when laying down are the back of head and neck pain headaches.
I suspect that those types of headache/neck-ache are caused by a restriction of CerebroSpinal Fluid (CSF) at the junction of the head and neck. A head/neck MRI would highlight this BUT don’t necessarily accept the radiologists report if it comes back ‘normal’ in this area.
What they are looking for is something called Chiari Malformation (Chiari 1, or CM1), which is where the cerebellum (hind brain) herniates through the hole in the bottom of your skull and down the spinal opening, by at least 5mm. Many of us on here have a much less than 5mm herniation and yet show very similar symptoms. A further explanation of the Chiari terminology, if you’re interested, is at:-
Many of the medical signs are very subtle and easily missed in the normal medical setting. I also show a copy of my MRI anotated with many of the things they should be looking for at:-