Feeling short of breath, dizzy, and heart palpitations... any advice?

I’ll try to summarize what’s going on, mainly because I’m terrified of actually seeing a doctor. No matter how much I try to convince myself I've figured it out or guess what's wrong, I know I have to face it eventually. Here is what I'm dealing with:
About five or six years ago, I first felt this shortness of breath—that specific sensation where it feels like your lungs just can't fully expand. That feeling would stick around for a week or two, then things would be fine for about six months before it hit me again. I’ve stayed physically active through cycling and tennis, and honestly, it never really seemed to interfere with my workouts at the time.
Then, early last October, things took a turn. One morning, it hit me out of nowhere: choking sensations on my left side and neck area, combined with heart palpitations. My blood pressure spiked to 180/110 and my heart rate was over 100. I went to the ER, and they basically gave me a sedative injection to calm me down. They also prescribed some Xanax to take until the course was finished, acting as if I was just stressed out about something.
Since then, things have actually gotten slightly worse. I don't feel the palpitations as often now, but I get this other sensation—that same tightness on the left side and a feeling of lightheadedness, like I’m about to pass out. It mostly happens in the evenings. Sometimes there’s weakness in my left arm or a dull ache when it hits. When that happens, I take a 1.5 or 3 mg Xanax pill, and the discomfort subsides pretty quickly.
I also deal with a frequent need to cough, producing phlegm that is either clear and sticky or white and sticky...
I’m 30 years old, and the worst part is how I’m handling this. It’s pathetic, really, but I’m behaving like a child because I am deathly afraid to go to the doctor for tests or imaging on my lungs and heart. Based on these symptoms, I’m convinced that's exactly what the issue is.

If anyone here has dealt with this or knows someone who has, please say something. Anything helps. This constant anxiety is killing me. I don't know where I stand, but the thought of a doctor telling me it's something life-threatening is paralyzing. At the same time, I know that by stalling on these checkups, I'm only making things worse for myself. I'm lost.🙂😕

Go get checked out, but I honestly doubt there's anything physically wrong with you. First off, if they only gave you a sedative at the ER after that episode, they wouldn't have done that if your heart was actually failing—they would've treated you differently. Plus, you felt better once that pill kicked in; if you had an underlying organic issue, a little Xanax wouldn't just make it vanish. You're dealing with panic attacks ☕

urbanseal2 said:I’ll try to summarize what’s going on, because the real issue is that I’m terrified of actually seeing a doctor. No matter how much I try to convince myself otherwise or play detective with my own symptoms, I know I have to face this eventually. Here is what I've been dealing with:
About 5 or 6 years ago, I first felt this shortness of breath—that specific sensation where it feels like your lungs just can't catch a full breath. That feeling would linger for a week or two, and then everything would seem fine for about six months before it hit me again. Physically, I’ve always stayed active—cycling, tennis, you name it—and I never really felt like it was holding me back during sports..
Then, early last October, things took a turn. One morning, out of nowhere, I felt terrible. There was this choking sensation on my left side and in my neck area, accompanied by heart palpitations. My blood pressure spiked to 180/110 and my heart rate shot over 100. I rushed to the ER, and they gave me some kind of sedative injection which made me feel better pretty quickly. They also prescribed me some Xanax to take until the course was finished, acting as if I was just stressed out about something..
Since then, through to today, things have actually gotten slightly worse. I don't feel the palpitations as much anymore, but I get these episodes where I feel unwell—that same choking sensation on the left side and a sense of lightheadedness, like I’m about to pass out. It mostly happens in the evenings. Sometimes I also feel weakness in my left arm or a dull ache when these episodes strike. When that happens, I take a 1.5mg or 3mg Xanax pill, and that unpleasant feeling subsides quickly.
On top of that, I often feel the need to cough; my phlegm is usually clear and sticky or white and sticky...
I'm 30 years old, and honestly, the worst part is that I'm acting like a child. It sounds ridiculous, but I am genuinely scared to go to the doctor for tests or imaging of my lungs and heart because, based on these symptoms, I'm convinced that's what the results will show....

If anyone has dealt with this or heard of someone with similar symptoms, please, anything would help. This constant anxiety is killing me. I don't know where I stand, but the thought of a doctor telling me it's something dangerous is paralyzing. At the same time, I know that by delaying the checkup, I'm only hurting myself more. I'm just lost at this point.🙂😕

Two things come to mind:
1.GERD

2. Hyperthyroidism

In any case, you should start with your primary care physician for standard blood and urine work, and then follow whatever path they refer you toward for specialists.