You're probably not allergic to smoke. I have allergies to mold and pollen and stuff like that, but ciggarette smoke and such make me feel really bad. What it is, is the smoke enlarges the vessels in your nose, causing the nasal congestion. In turn your body produces mucus causing the scratchy throat in the morning. what is simply happeneing is it is irritating your sinus's and nasal passages. The stuffiness over the long term causes blockage in your sinus cavaties which the mucus gets stuck in, causing sinus pressure. And over time you can develop an infection, thus having a sinus infection. Take it from me, someone who has had one too many infections. Take care of yourself and avoid those situations.... i won't go to a bar that allows smoking anymore.

Yeah, people have been taking a casual attitude toward second hand smoke for far too long. It'll kill you just the same as if you were the smoker. Keep away. Regarding avoiding the sinus infections etc, make sure to keep your sinuses hydrated--when they get dry things like smoke can irritate them to the point that they become infected. You should go armed with some saline nasal spray and "shoot up" to keep the tissues good and moist inside your head! (NOT the "medicated" stuff, just plain saline spray, there's a brand name called Ocean but most of the chains have a house brand, it's cheap). Same applies if you're flying or staying in hotels, wherever the air might be stuffy or dry.
Regards,
Richard Day Gore