Ok, so when I was about 16 up until I was about 19, I was having issues with palpitations and very mild chest pain and left arm tingling, I usually ignored it and it would go away eventually, but a few times I did decide I should have it checked and went to the ER. Usually during the ride there or while waiting in the patient room, the pain would leave and so would any palpitations, so every time I'd be hooked up to the monitors, have blood tests and urine tests(they always seemed to think I was on drugs since I was so young and also very thin), they'd always come back near perfect, and they'd say "Its just stress or anxiety, probably" most of the time. One doctor did say something about tachycardia on the very last visit I made back then and referred me to a cardiologist, which, quite foolishly I think now looking back, I never went to.

I changed my diet for a time since it was horrible(I mean, I drank probably 5-6 12 oz cans of Mt Dew or Dr Pepper or Coke every day for years) and cut out all of the carbonated drinks and caffeine, cut out all fast food and within just a few weeks it really was like night and day, all the symptoms seemed to poof.

Fast forward a few years to now, I'm 23 and almost all of the symptoms I used to have come back, but only worse. The only symptom I used to have that I don't have now are palpitations. I few days ago I had been on the computer late at night reading about some things and had the sudden urge to pee; well, I went to pee and right after that I got a "rushing" feeling( I cant describe it) starting from the bottom of my abdomen and going all the way up to my chest, then I felt like I had to throw up, then I started sweating even though it was like 50 degrees in the house, then I got another rushing feeling that was 5x worse than the first one and I almost passed out right there. at that point, I had someone take me to the ER, and they rushed me back in ASAP, even though most of my symptoms, surprise surprise, had already left by then. Of course, got hooked up and monitored for a few hours, took a urine test, a blood test, an X-Ray and all came back perfectly clean. Ever since that night though, I have felt really tired, really weak, occasionally dizzy and have dull pains in the top left corner of my chest, my left arm, sharp pains in my head and occasional dull pains in the left of my jaw. I really don't think all of this caused by stress, I really have nothing to stress about.

This isn't worrying to me because I'm afraid I'll have a heart attack or something like that, it's worrying to me because I am a musician - that's all I do, I am ~very~ poor and do not have insurance. If something were to happen to me my family would have to pay the very large costs associated and I really don't want to consider that as an option. I want to know how I can have the doctors really seriously take into account everything I say, without just saying "you're too young" or "you're stressed out, chief" and how could I get seen and have all the appropriate tests done knowing I do not have insurance? Also, is it possible that it's something that isn't heart related, that just mimics the symptoms of heart disease?(not including stress).

I don't know if any of these things are important but I'll list them anyway:
I'm male. Some of my family do have heart problems, my aunt has mitral-valve prolapse. My dad is a cancer survivor, my mom also had cancer. Since that one night that I stated above, I've also had a really weird/sore feeling on the left side of my crotch area, not sure if that's even remotely related to anything but you never know :V