Shopify store only show multiple currencies under the USD convert rates instead of 100 usd in USA, 100 CAD in CA, 100 EUR in Europe unless you register multiple domains for multiple stores.
In addition, USD:CAD=1.24, the sam product cost sell to Canada higher than USA as the shipping, tax higher, that means the product price you plan to sell in CA at least 40% cheaper than USA while USA is even bigger market, that doesnt make sense at all.