Im a 41-year-old guy and lately, I've been really struggling with breathing. It doesn't matter if I'm just sitting, standing, talking, walking, or pretty much doing anything - it's like I'm always short of breath. A month ago, I had some pain on the left side of my chest and ended up doing a bunch of tests like ECG, Stress Echo, and a chest X-ray, but everything came back normal. I'm really puzzled and kind of worried. Why do you think I might be feeling this way?