Mild headache, mild stomochache, dark stool,mild pain in neck and burning sensation or pain in hearr

Patient: Hi i had fever last week for which i was hospitalized for 4 days, i don’t have fever now and discharged but have to continue some medicines (supradyn, vitcofol and becosules) but now i have constant burping, mild stomach ache(no fixed place), mild headache(no fixed place), dark and sticky stool, mild pain in my neck and shoulders and sometimes burning sensation or pain in chest or lungs!!! is it something serious???

Doctor: