I had an ecg (electrocardiogram) done when they were checking for possible heart problems a few years ago but that's the only one I know about (and it's not uncomfortable of anything)

I had a chest x-ray as well.
The most important tests are the physical ones though (listening to your heart...Etc and electrocardiogram as moo said.
An ultrasound scan is also used although I don't think they really will want to use that unless they discover something wrong in the other tests.

I had the ekg and heart monitoring, and some blood tests.

So if my ecg comes back normal does that mean theres deff nothing wrong with me?

I think so. I believe any heart abnormalty would appear on the ekg, and for things like mitral valve prolapse(which in many cases is not the least bit harmful) the doc can hear by just listening with the stethoscope. If you had a major problem, it would have shown up.

Actucally my sister had a ekg and nothing appeared. The doctor decided for her to wear heart monitor for the day and they found that her main vein was shooting blood back in the heart-which causes her heart to pump very fast....

These are the tests that I had done:
chest x-ray, ecg, ultra sound of the heart, 24 hour monitor, stress test (treadmill), breathing test, body scan, blood tests - I think that is it.

All came back clear - thank god