I feel like I am not able to get enough air when i take a deep breath, but not constantly. It happens for a little while almost every day. This has been happening for around 2 months now; it started after I went to the gym and pushed myself to run faster for a long period of time than I should have. I've also noticed that I clear my throat frequently due to the feeling of mucus at the back of my throat. Do you know if there's something wrong?