Thanks for your question on Health Care Magic. I can understand your concern. Sudden onset severe left sided chest pain is mostly seen in heart diseases. So better to get done ecg and 2d echo first. If both are negative for cardiac pathology, no need to worry for heart diseases. Possibility of lung related causes is also less because you are not having cough or fever or sore throat. But better to get done chest x ray to rule out lung causes because you had ARDS in past. If all these investigations are normal than possibility of muscular spasm is more. So take painkiller and muscle relaxant drugs. Avoid heavyweight lifting and strenuous exercise. Don t worry, you will be alright. But first rule out cardiac cause Pulmonary causes. Hope I have solved your query. Wish you good health. Thanks.