It seems that your upper respiratory infection
has travelled down to your lower respiratory tract
and you may have developed lung infection
. The pain could be pleuritic due to involvement of pleura
. You should get at least a xray chest, routine blood count and a USG abdomen to rule out sub diaphramatic pathology. If these are normal it could be simple gastritis
as a result of medicines you have taken and you should take pantaprozole for this. But if the ivestigations point to wards a infection, you will need a course of broad spectrum antibiotics and other symptomatic treatment for which you should consult a physician or pulmonologist.