Had a heart ultra sound, cta, and event monitor 6 months ago. if i had hypertrophic cardiyopathy it would've showed right?

Yes: I would not be concerned unless you are an athlete and have collapsed on the field and the tests were positive for an abnormality. The cardiac cta and an ultrasound/echo should've picked up any cardiomyopathy. Of course you should be consulting your pediatrician or pediatric cardiologist for complete details.

Correct: Being the tests were normal there is no possiblity that you have that diagnosis very unlikely at this time.