Hi @Carlos_Hidalgo, great question! 
There is currently no way to access a specific page query from Global.
From our doc on Multipage Apps:
"Page-scoped code and components can only be referenced within the same page."
We'll share any updates if there's movement toward changing the scope of queries across pages. On the meantime, could you expand a bit more on your use case?
Is getStores a page specific query that we are trying to trigger from another page?