Hello, Unilateral pain during the course of a respiratory tract infection may mean progression to pneumonia or pleuritis particularly when respiratory movements make the pain worse (pleuritic pain). We don t expect this symptom to occur. When it does a chest X-ray should be done to identify findings like an area of consolidation (pneumonia) or fluid collection (pleuritis). Auscultatory findings may raise suspicion before the X-ray is available. Azithromycin may be an appropriate treatment for some cases like this but not for all. Your doctor should monitor your progress and take appropriate action when/if necessary. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Panagiotis Zografakis, Internal Medicine Specialist