<s>[INST] Im A 20 year old male and ill get a feeling like i cant breath and then feel like im going to pass out and my body gets tinlgy but then it goes away and will come back later on i went and got tests done and my heart is fine the doctor said? what could this be? [/INST] Hello dear, Thank you for your question, It is common among young men to complaint about breathing problems. Your young age and the lack of history indicative for pulmonary disease suggests that you might be suffering from stress. There are some tests that you can run in order to be sure and help recover from this stressful situation. Since the test performed on your heart came back normal, it is safe to say that there is nothing to worry about. I always suggest my patients to engage in physical activities, meditation, healthy diet, engage in social activities and avoid excessive intake of alcohol, cigarettes and coffee. If your problems persists you might seek help from a professional specialist that can help manage stress. I hope this helped. Kind regards,  </s>