When I go into my inventory, and I click on the item I would like to put in my shop and then click add to shop, it is blank where it should have my shop listed. I can't do my quests. Please help?!

when you hover over the "your shops" link in the commerce dropdown, does your shop have a symbol next to its name? if so, that means your shop is still on the old shop system and can no longer be stocked. you'll have to create a new shop, move everything from the old one to the new one, and delete the old one. this thread explains further, if this is the case. New Shop Guides