Wet phlegm cough 5 days post op, is this a sign of complications?

I had breast augmentation 5 days ago under general anesthesia. Four days later I started coughing throughout the day, wet coughs where I am suddenly intensively coughing up phlegm. Sometimes my lungs slightly ache after from hacking so intensely but it doesn't hurt my incisions or breasts really. Is this a bad sign or cause for concern?