I've been getting a strange sinus pain on the right side of my face and head only after reaching cruising altitude. It feels like a really bad headache. Then after descending it goes away. It only happens after being at cruise altitude for 10 or 15 minutes then it hits and won't go away until descent. It is nothing like a middle ear block. On the ground and in the climb and descent there are no symptoms at all. I had a cold 2 1/2 weeks ago but feel fine and didn't have this problem until recently.