Beginner question. Any answer welcome :)

Could any one point me to the right direction on how to manage the stock of my items since i am selling items in the physical store as well? I mean the inventory of my eshop and physical store are the same. Editing the stock of the eshop each time i make a sale on my store is a tedious and time consuming process. Is there a fastest/easiest way to do it through a plugin or via another method? Googling this did not help me at all so any tip would be highly appreciated. Thank you 🙂