hi lined in silver.
I think with the kind og gastro symptoms you are mentioning, you should have a consult with a gastroenterologist. And yes, you probably do need a referral, all depending on your insuranse. I have a open acess insurance, so I do not need referral. But you live in Canada, do you not? So then, yes in your healthcare system you need a referral.

You might need to be tested for autonomic neuropathy and this could be the reason for GI fullness. and burning.

You might need a test called Gastric Emptying study to rule out gastrophoresis. If you have this, you might have to be on small frequent meals, and on a Acid reducer such as Protonix.