I had a really nasty chest infection a few months back, with the preceding bug it took a while to clear and I had a lot of pain with it. I was checked for pleurisy, as I'm at a greater risk of it, but none found and I had a chest Xray done too. So mine was painful even without pleurisy.
It went away as the infection cleared up though it took a while, was just things aggravated by it, especially all the coughing I think. Did you have the pain when you saw the doctor to get the antibiotics, I'm assuming they had a listen to your chest then?