Symptoms returned

It sounds like anxiety and maybe some panic. Anxiety is awful. It can play many tricks on the mind and body. It will come out of no where. I've had it on and off your many years . You can be going along good and wham it shows its ugly face. Also when you see the doc you will feel better for days, but then a small thought of something like what if comes along. What if is the worst 2 words for people with anxiety. When you feel weird symptoms it can cause your heart to race, adrenaline to go up that will cause chest pain, breathing to be labored and this will cause you to over breath a make it feel like you can't get air, dizziness (this is my worst symptom) shaking, weak legs, neck pain, muscle aches and tons of other symptoms. Pribably when you started to run you were thinking about your chest pain and of course chest pain comes with breathing problems which will cause lightheaded passing out feeling. Try to remember and I know it's hard but the doc said you are ok, if they thought it wa your heart they would not send you home. It's very hard to convince yourself your ok.

Maybe see your GP and see about something for the panic and anxiety attacks and if that helps then you'll know it's not your heart. That's what I had to do years ago and when the Xanax helped I knew I was ok. I take it only when I absolutely need it. I hope you feel better

Remember this saying once an attack starts: "This shall pass!"

I had panic attacks in the past and at first I really wasn't sure what to do, or how to react to them! First, my heart rate would rise, then I'd start sweating, then breathing becomes difficult, lightheaded, and on and on. For the life of me, I could not understand what the heck was going on! So, after talking to my doctor, having some tests done and finding out that everything was within range, I began to realize that what's real actually may literally be my mind playing tricks on me!

So what did I do? Remember that phrase at the top? "This shall pass"? Well, I found out (through extensive research on the internet and speaking to healthcare professional friends of mine) that panic attacks WILL PASS! Something happened to your body chemistry that led to the attack and it "fooled" your system into believing that something terrible was about to happen to you! As a result, your body goes into protection "fight or flight" mode! Either way, fight or flight, your needs to get the adrenaline and other systems ready so the body takes off and you aren't prepared or expecting this! And if you start "freaking out" you're just going to make it worse! It will pass!

If you experience a panic attack what I would suggest is not fight it. Don't add more panic to the panic that's onsetting. It's a viscious cycle as I have discovered and when it happens, if you worry even more about what's happening, it makes the experience even worse! So, what you need to do is tell yourself, "This shall pass!" then just let it happen - most panic attacks aren't very long - and prepare to be tired as heck once it ends!

If you're athletic - you mentioned "preparing to run" in you comment - and you feel an attack coming on, I probably wouldn't run or exercise. I'd just let the attack happen, tell yourself this is normal when these attacks occur and don't fight it! 

Good luck! Hope you feel better soon!