<s>[INST] I was sitting still at my work, talking and all of a sudden my chest tightened and my heart was beating heavily, not really fast and it was hard to breath. I held my chest and tried my hardest to breathe slowly and catch my breath and after a few minutes my breathing feels normal, [/INST] Thanks for your question on Chat Doctor. I can understand your concern. Sudden onset bronchospasm due to either stress or allergy can cause similar symptoms. So better to consult pulmonologist and get done clinical examination of respiratory system and PFT (Pulmonary Function Test). If PFT is normal then no need to worry about lung pathology. Rarely Pulmonary embolism can cause sudden onset chest tightness and breathing difficulty. So if PFT is normal then get done CT Pulmonary angiography to rule out Pulmonary embolism. If this is also normal then possibility of stress and anxiety related symptoms is more. So avoid stress and tension, be relaxed and calm. Don't worry, you will be alright. But better to rule out above-mentioned causes. Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks. </s>