I have had a cold for over a week now. I also have really bad allergy problems. This morning I was coughing hard. Which I have been doing for a few days because of the cold. Well I coughed up a white chalky hard substance. To me it looked like a tooth or popcorn. I have no idea what this is and this is the second time in a few days I have coughed this same substance up. Wondering if anyone knows what this could be or if it could be a sign of pneumonia.

Thanks