Thanks for your question on Healthcare Magic. I can understand your concern. Your chest tightness, pressure and heaviness are associated with specific position, supine with right side down. This can be seen in right sided pleural effusion (collection of fluid in right pleural cavity). So get done chest x ray first. If chest x ray is normal then no need to worry for pleural effusion or other lung diseases. Sometimes stress and anxiety can also cause similar symptoms. So avoid stress and tension, be relax and calm. Don t worry, you will be alright. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.