Just thought I would share some experience with this.
About 6-7 years ago when I was taking propecia I began waking up feeling worse than before I went to bed. I can’t believe it took so long but I finally figured out my “feeling bad” was mostly from severe jaw clenching/grinding overnight. I felt terrible most days even after sleeping about 8 hours. My headaches were even worse after sleeping longer than 8 hours or if I was anxious about something.
Finally went to the dentist and he confirmed I was a clencher/grinder. I got a cheap boil-and-bite mouth-guard and for a few days felt excellent, 0 headache. Finally I had a few nights of sleep like I had before I started taking propecia. Unfortunately, a few nights later I must had adapted and chenched harder. I even woke up a few times finding myself biting and chewing hard. While guards help protect the teeth, apparently they may not do any good to reduce clenching and might even make it worse.
I was so desperate for some relief I got 15 units of Botox in each masseter muscle. Very expensive and insurance likely wont cover it. (some insurances may cover if you get chronic migraines).
It’s been about 2 weeks now and 0 headaches. I have been sleeping better also. If I sleep 8 hours, I wake up and I feel like I slept 8 hours. Granted my sleep is still screwed up from propecia and I have nights where I wake up some 15 times.
I don’t imagine this applies to many of us on here. I only remember a couple people mentioning they get headaches a lot. If you get chronic headaches you may want to look into this more.
This site might help identify if your masseter muscle is tight.