I have had a cough for 3 days now. It's terrible and painful and I cough up yellow/green phlegm. However, I don't have any other symptoms beside a sore throat, which I assume is from coughing. Any idea what this could be?

You have a throat infection.if it continues, you may want to go to Doctor for antibiotics.make sure you take the entire prescription, people often make the mistake in stopping before hand if they feel better.this is a bad mistake since stopping antibiotic before total dosage is administered will cause the antibiotic to loose the ability to work on you in the future because your body creates ways around it since you havent completed the medication prescribed.

Vera