Blood spots in my mucus and persistent cold?

I've had a cold for three weeks. I'm still coughing and I still have a runny nose. They both won't go away. But a few minutes ago I blew my nose and blood spots were in it. I dabbed the inside of my nose because maybe it was dry and there was no blood. I'm concerned seeing as how i've had this cold for so long, and when I cough it hurts my chest. I have a burning feeling. Do you think it's just a cold? My phlegm and mucus has been bright green for three weeks also.