Light brown specks in phlegm/sputum?

I work outside, and it's winter time, so naturally I got sick from the cold weather. it started in my head and went to my chest. I have since recovered, bust still have a slight cough, & I sound like the grudge when I talk. I smoke marijuana daily (through a glass pipe usually), and am pretty sure this has attributed to the very dull pain in my chest (on the right side, below my collar bone) as well as the coughing. since the sickness, I have quit smoking to give myself time to recover, but am quite concerned about the brown specks I cough up in my phlegm. Any thoughts?