I've recently had sudden onsets of chest congestion and yellow mucus in my spit. I could be completely fine one hour and start producing the familiar sound of chest congestion in the next. I don't have a runny nose but I may produce yellow mucus when the symptoms begin again. The time lapse between having 0 symptoms to feeling congested can happen in minutes and go away in an hour. I've felt this way for roughly 37 days and am unsure as to what's going on. My girlfriend had mono 47 days ago, and I believe I may have it too. But the unpredictable nature and brevity of my symptoms has me completely unsure as to what I'm experiencing. Please advise.