I used to do yoga. I started as a way of increasing flexibility for my martial arts, but I found my general health improved and I was less stressed too. My blood pressure dropped too which was a great bonus.
One of my friends who has always been very hyperactive (probably an understatement!) has taken up yoga and has never been so relaxed!
Sinuses. Well, I've always had sinus problems. I've had my nose broken a few times and have a very deviated septum. Initially the cpap caused more irritation and I used a decongestant half an hour before bed for this, but now I'm finding my nose is better than it's been for as long as I can remember. The cpap seems to have improved all aspects of my breathing. I used to be a bit erm 'phlegmy' in the mornings...probably for 25years I had this. Now I'm not at all. I'm really pleased about this.
I think it's maybe just a matter of more time needed to adjust that's needed.
Best of luck