Should I Push for a Nuc Stress Test?

I recently had a stress echo done because I have been experiencing exercise induced chest pains for nigh on two years now. The results of the test came back normal and the heart seemed to be in good condition. I was content to leave it there until I read that one can pass the exercise stress test and the stress echo even with severe blockages. I am now wondering if I should push for a nuclear stress test and a coronary cath to see if I have blockages. I am only eighteen and my cholesterol is at a reasonably healthy level, but my HDLs and LDLs are at a poor ratio, to the best of my knowledge, and my triglycerides are far to high. I also am overweight by at least 30 pounds and have been for my entire life and I have hypertension. I eat a diet that is high in sat fats and all sorts of other nasties. I don't think I have any severe blockages, but I believe that I have blockages.

[Flycaster305]

At your age and situation, I'd suggest you probably don't have a blockage.  A heart echo would seem to be a better test, given your age and history.  Keep in mind, I'm not a health professional.  
That said, by your own admission you are at risk for arterial heart disease in 30 years and suggest you mix in a healthier diet, and the nasties you mention should be evaluated...
keep us informed.