Quick question particularly for any nurses out there in cyberspace

I have a horrible cold (bordering on man flu), it really hurts when I have to cough but I am coughing up green gunk. Should I take an expectorant or not? I sort of don't want to have to cough more (have pulled muscles in my stomach and it burns down to my lungs when I cough) but then again it's got to come out someway. Any ideas?