Hello You are having night sweating , fever , sinus infection ( chest pain ) almost from last 4 weeks . Still no relief with amoxycyclin capsules , even you developed stomach pain . In my opinion this stomach pain may be due to hyper acidity or gastritis due to fever and medicines , so only antacid syrup will help for this stomach pain. Now the main question about chest pain , fever , flu like symptoms , these may be due to . 1 Tuberculosis , due to long history of illness with chest pain and infection is an indication of tuberculosis . Diagnosis can be confirmed by X RAY chest and blood for E S R and c b c . If sputum present get its examination. 2 Allergic bronchitis may be the next cause so get in physical examination by a physician . 3 Pneumonia or pneumonitis may be the another most common cause . Xray chest will find out the exact nature of illness. In my opinion consult a physician and get his opinion. As typhoid fever is most common cause of long standing fever. Good luck.