I agree it might be a bit unintuitive to even find a store Wall, unless you know where to look for it. When a user clicks on a store in the side bar, main store page with pickups will open (and this is OK as pickups for the store should be a default page), however, side bar won’t display sub-pages available for the chosen store, i.e. Pickups, Wall, Feedback, History, unless a user scrolls up:
It could be much easier if all the sub-pages were also displayed at the top as this is probably how a user naturally searches for any type of navigation:
If such top panel were available at each sub-page for each store, navigation would be much easier.
As far as this comment is concerned:
I would suggest asking users for a reason. It’s still a new feature, therefore, they might not know / remember how to use it correctly. Moreover, in each case it’s worth reminding them that store-related discussions should be moved to store walls.