You have to submit the questions to the "Ask a doctor" section. Go to the top of the page and click on the "Ask a Doctor" tab. It sometimes takes a couple of days and with your vague symptoms, you may not get much of an answer, but you are welcome to try.
If it is a dull ache, I think there is a good possibility it is muscular pain, but regardless I think you should see another doctor or go back to the one you've been going to.
I'm currently getting over something similar after pneumonia and pleurisy. Apparently the pain made me tense up my muscles and I didn't un-tense them when I got better. The physical therapy is really helping. If you push on some areas, does it really hurt, like a bad bruise, even though there isn't one? That's how it is for me. The rest is a dull ache and a sharper ache when I take a deep breath.
Go ahead and try posting your question for the doctor. Just be REALLY specific about you symptoms or all you'll get is him telling you he doesn't have enough information and you should see a real doctor. Good luck. Let us know how it turns out.