I've had bacterial pneumonia once before and I'm feeling the same way I did then, prior to the very high fever that finally made me go to the doctor who sent me for an x-ray and determined one lung was filled with fluid. Up until the fever, the only symptom was chest/pectoral muscle/arm pit area pain that made me feel like I'd pulled a muscle and I had been feeling like that for months. Now we have to wear full breathing masks at work, 8 hours a day for the last 4 or so weeks, indoors and out, heavy labor, in the heat extremes and I feel the same water logged chest pain. Can rebreathing my own exhalation day in and day out cause a respiratory illness?