No no no! The heart?!

Hello peeps, I'm new here, and although I hate to ask a lot of everyone so soon, I'm in need of some advice.

As you can probably tell from the title of my post, I'm worried to no end! I have an echo coming up on Tuesday, but based on today/tonight's symptoms I'm now pretty convinced they're going to find something wrong with my heart. I've had a tight chest, dizziness and palpatations all day despite a good night's sleep. I even have had trouble belching - something I made the mistake of Googling in the past, and finding out it COULD be related to cardiovascular problems, including heart attacks. I'd be more ready to accept these as anxiety if that's all there was to it.

Just now when I finished eating (and earlier when I stood up out of a car) I felt a shooting, mild pain moving from my left shoulder to my hand. Suddenly felt a surge of pressure in my chest, and my heart started to pound more rapidly. The left of my chest just under the armpit mildly hurt constantly, and felt rather full. Even now, I am still experiencing discomfort in my left arm and shoudler, and tightness in my chest, a full 30 minutes after.

The pressure and pains only lasted a few seconds - 30 tops if put together - but the long-term discomfort has convinced my horrid mindset that I've had a mini heart attack or PVC and not realised. I dare not Google anything, as I have already had a very stressful day (family, health and work issues alike), so any advice is much appreciated as always! For the record, I'm a 21 year old guy, very skinny and more active than the average person, and I've suffered anxiety all my life... just not like this..! ^^'

I don't think its heart attack related, but it might not be a bad idea to go and get checked out. They will most likely do an ekg and bloodwork.