All you need to do is to make a view (drupal 7, views 3) and teach me how to implement it on my site.
Content Type Article
Both Article and Store Vocabulary have a term reference to Vocabulary Category. (Articles are tagged with category and stores are tagged with category as well).
This view will be shown on Article node pages as views block and will show stores from same category as the article page.
No theming, no code, nothing else is required. It can be done by contextual filters but I dont have time.
You will use your own server and will just provide me the view code to import and explanation of how it was done.