@gabrielm just to introduce myself, I am a 28 yr old female who is otherwise healthy..

I can't believe I'm just seeing this thread now. Everything youve described in your original post is everything that has been happening to me, except my sob started August 2019. It came out of nowhere and has never went away. Originally I had went to the ER and the doctor was convinced it was a blood clot. They did blood work, chest xray, TWO CT scans (one with oral dye, and one with intravenous dye) , and also had an ultrasound of my heart to make sure no build up of fluid. The only thing they found was on my chest xray there was a very small amount of air in my chest cavity. I was sent home being told it would resolve on its own and they set up a follow up appointment with a thoracic surgeon to make sure it was clearing up.
I saw that specialist about 3 weeks laters, and had another chest x-ray done. They air was still there but they were still confident it would resolve on its own. I went back a month later, air was gone (or was at least so small now that it was undetected on yet another chest x-ray) and now I had a new symptom; when I laid on my left side (which was the side with the air stuck) and I was propped up with a pillow under me, say, sitting on the couch, when I took a deep breath I could feel these little air bubbles coming up under my ribs, I could hear it sometimes too, it sounded like actual little burps coming from my ribs. Doctor said that was the air releasing, yet to this day, I still have that symptom.

Went back 3 months later because although the sob never completely went away, it was manageable, and some days I forgot it was even there, and then I had a "flare up" and it was quite bad one week so I returned to the specialist. Had another chest x-ray done and it was normal. He did not know what was wrong with me. He said he would schedule a pulmonary function test. This brings us to April 2020 and with covid-19 , I cancelled because I didn't want to go to a hospital. However a week after I cancelled, I had another bad flare up so I called and booked the test.
Pulmonary function test came back completely normal.
Next thing the doctor wants to do is a bronchoscopy.
I'm so frustrated. I feel like my deep breaths won't catch. It's all I ever think about. I'm always so focused on my breathing which I'm sure isn't helping.
It's reliving to know there are others like me out there..