From Tweco: OK time to set things straight here, you people are throwing out some crazy answers here. All this talk of gas contamination skip breathing is just nonsense. With out symptoms like lightheadedness, euphoria, lack of concentration, decreased motor skills it just is not likely at all. connect the dots Headache and vomiting. You have sinuses up there and your middle ears are connected aswell if you are congested your sinuses cannot clear thus a pressure difference forms in you middle ear cause alte...