Thanks for your question on Health Care Magic. I can understand your concern. By your history and description possibility of musculoskeletal pain due to pulled muscle is more. But better to rule out internal lung pathology first. So get done clinical examination of respiratory system, chest x ray and PFT (Pulmonary Function Test). If all these are normal then no need to worry for major lung diseases. Musculoskeletal pain is more likely in your case. So avoid heavyweight lifting and strenuous exercise. Avoid movements causing pain. Avoid bad postures in sleep. Start painkiller and muscle relaxant drugs. Apply warm water pad on affected areas. 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.