How's your pillow(s)?
Most average pillows pick up allergans and dust, or worse... and the filling loses its volume and thus doesn't give your neck support... which leaves your back at an odd angle which puts your hips at a weird angle, or if your knees out of alignment they'll do the same thing. Some people don't notice it, but for others it can cause chronic back pain... which will keep you up forever and ever
My knees can be at any angle and not bother me, but if my neck isn't in an agreeable position when i fall asleep, I'll have headaches all day the next day.
I bought some fancy friction foam pillows that hold thier shape to whatever you pack them into, and they were worth every penny (cost 100 bucks each!). Sleeping was so much easier after we got those pillows.
Does your back, neck, or shoulders bother you, or have they bothered you at all over the past few months?
MKIIINA has some good points! More details.