Hello Welcome in H.C.M. I have gone through your query regarding pain under breast right side from front to back and it become more severe on coughing and lying down. Considering all aspect of your symptoms it appears as you may be having either of these- (a) Pleurisy right side. (b) Sub diaphragmatic abscess. (c) Congestion in Liver. So it will be better to consult any Physician for thorough examination and necessary investigations to pin point the diagnosis and plan for treatment. Regards.