Hello Welcome in H.C.M. I have gone through your query regarding pain over collar bone on coughing. As you said that you are smoker and your cough is quite severe and already 4 days had been passed. The pain at the collar region on coughing demands investigation and physical examination to rule out pneumonia (apical). To establish a diagnosis you should do- 1- X-Ray chest . 2- Sputum for Gram s staining. 3- Culture and sensitivity of throat swab. With the help of above investigations and thorough physical examination by your doctor your problem may be diagnose which may be accordingly manage. Regards.