What Causes Recurrent Coughing Despite Having Complete Pneumonia Treatment?

My 2 1/2 year old had been diagnosed with pneumonia about 2 weeks ago. It was caught on a chest xray and the hospital called me two days later to tell me he had pneumonia after dismissing it as a stomach virus. He was prescribed Azythromicin (sp?) He took it for 5 days and seemed to be fine after that for about 6 days. No cough, no fevers, nothing. Now he has been running a fever of about 102.5 for the last 2 days. I have been giving him tylenol and motrin alternating. He doesn't really have a cough, just a little tiny cough here and there (not enough to consider a cough) but I am very concerned. If I take him to the hospital again I feel like I will be dismissed easily (it took them two days to realize he had pneumonia) I am wondering if it is possible that this is his pneumonia either coming back or not cured at all or if it could just be another virus. We are between general pediatricians right now, I'm not sure what I should do