@jillian22, Did this come on rather suddenly? I ask that because of my own experience. My background: I am a liver/kidney transplant recipient and I take immunosuppressant medications for 10 years. A couple of years ago, one of those meds, prednisone, was discontinued and that is when I began to experience my SOB.
I have always struggled with uphill hiking, and blamed it on not training enough. However, I had been doing real well until the prednisone was lowered. (In hindsight, the belief is that the prednisone had been masking my exercised induced asthma and when it came back it hit me particularly hard) We were hiking and I couldn't catch my breath, even walking was strenuous and I needed frequent sit-down breaks. I made an appointment with my PCP and saw him as soon as we returned home. My PCP acted quickly and arranged me to see pulminologist and cardiologist. Lungs and heart checked out perfectly. The pulmpnologist was able to narrow my problem to being exercise induced asthma - I am not suggestion that this is what you are expereincing, however, before he helped me get it under control, I was experiencing a tightness in my chest and could not get enough air into my lungs. https://www.mayoclinic.org/diseases-conditions/exercise-induced-asthma/symptoms-causes/syc-20372300

Now back to my original question-Have you made any recent changes to your environment (new location, new bedding or furniture, medications, detergents)? My symptoms are triggered by heat and humidity, and the pollen and grass.
I know that you are afraid. I hope you can get some answers soon. When do you see the pulminologist?