I agree with Blossom, mostly. Lots of people (of all races & ethnic backgrounds) cannot tolerate dairy, especially milk. It made my sinuses stuffy, and caused phlegm in my throat, and constant ear infections. Doctors didn't help me; I had to find out by myself by eliminating stuff from my diet.
I wouldn't recommend soy products; they can be irritating to your mucous membranes too. I tried them and was still stuffy. If you want something milk-like to drink, try almond or rice milk. I use a little rice milk, but not very often. I take a calcium/magnesium supplement for the calcium.
Try avoiding fruit juice, especially orange juice. Try avoiding anything cold, chilled, or icy and frozen. You may be surprised. I was!