The general picture - fever / sputum / then fatigue
- is one of infection...
X-ray is a point of concern - especially upper lung may point to tuberculosis
...one should go for blood tests / sputum and so on - especially if the blood count shows a high ESR. Some times, a CT scan
of lung and/or bronchoscopy
may be needed. Every effort must be made to evaluate the nature of shadow - it should not be left easily.