To have Facebook as a sales channel, your product must require shipping. Since my products are digital I set the shipping weight to 0 lbs and made my shipping rates 1 lbs and up. I also changed the "shipping address" to "customer address" in the shipping section of the checkout cart language under settings. Here is a forum entry which gives a little perspective on the issue from another Shopify merchant.
Once I made the above changes, every product from Big Band Chart Store that had a shipping requirement added (whether it was a digital product or not) very quickly populated my Facebook page at Bill Fulton Music. The products are also available through the Facebook checkout further streamlining the order process.
IMPORTANT UPDATE! Make sure your default package has a weight of 0 (zero) or it will automatically add the cost of the default packed to digital products which have no weight.