You're right. In the US, and I presume in Canada, you need a prescription for ANY drug that isn't OTC [over the counter]. Controlled substances are normally narcotics. They cannot be 'called in' to a pharmacy, they require a written scrip, along with the doctor's ID#, and they are kept track of.
I remember a few years ago when Mr. AE got hurt, I took him to the ER where they wrote a prescription for Percocet. I went to RiteAid to fill it, and the pharmacist advised me that he could not fill the prescription. Why? RiteAid had identified the doctor as writing too many scrips for controlled substances. Well DUH, he's an ER Physician! I left, went to CVS, got it filled in 5 minutes, and haven't stepped foot back in RiteAid since.
When I travel to DR, I have a ziplock bag filled with all sorts of painkillers, many controlled, but in their original bottles. I bring them "just in case". They're in my carry-on, and no one has ever questioned them in either direction.
Maybe I just look like I'm falling apart or in pain, haha.