I have constant sinus problems. One thing I have found particularly helpful, and which I do 3 x daily, is head drainage exercises.
1. Put your forefingers either side of the bridge of your nose, and either pull down or push up (whichever is more comfortable). Do this for 7 minutes per time for 10 days, and then 1 minute per time after that. The 1 minute exercises can be repeated as often as every hour.
2. Stroke the front of your face with the palm of your hand (20 secs). The fingers should roughly separate either side of the nose.
3. Stroke the sides of your head from above the temple to the jaw (20 secs)
4. Stroke the back of your head down to your neck (20 secs).
Quite difficult to describe, but hopefully you understand.