Rexall is definately around in Canada, at least in Alberta. They sponsor everything in Edmonton. They were the title sponsor of the Indy Car series race last week. They own the naming rights to the Edmonton Oilers' Arena, Rexall Place. I'm pretty sure their logo adorns dasher boards for every NHL team in Canada. They seem like Canada's answer to Walgreens.
Not sure if I would go that far (Shopper's Drug Mart seems to be larger) but yep. We have them pretty much everywhere. No Walgreens up here either.
I remember shopping at a Woolworths with my mom, picking out a Seaview submarine model kit (From Voyage to the Bottom of the Sea) and having lunch at the counter. I had a Burger and a Coke while mom had the Tunafish on toast...ahhh those were the days....