Intolerance Testing (For Casein/soy/etc)

Hi All

So, since I keep having new problem foods popping up every other day (exaggerating, but it's getting frustrating), I think it's time I looked into some further allergy/intolerance testing.
I haven't been tested for anything since two negative blood tests for Celiac (technically, I self-diagnosed and went on the gluten-free diet cause I didn't want to suffer longer to get a biopsy, and Celiac runs rampant on both sides of my family).
I am 3.5 years gluten free, and now casein and soy (almost) free.

Does anyone know of any reliable tests for food intolerances? (not allergies)
Do you think it would be a good idea to get allergy testing done as well, just to see if there's anything else going on? (aside from mild hayfever, I don't have any)
Or is a strict elimination diet really the only way to go?

Also, what kind of doctor/specialist would you go through to get these test?

FYI: I'm in Toronto, Canada.

Thanks a bunch
Peg