I was an assistant manager at an Ohio based drug store for a few years. My day to day duties could range greatly: scheduling, product ordering, finalizing and double counting the book keeping, supervising 8-16 employees, customer service (shitty employees sent the pissed off customers to me), stocking shelves, planograms, inventory, backroom management, covering the departments if short, ect.
A lot of the time I would honestly say that I was a glorified stocker/baby sitter. You do a lot of the same as the head/store manager but as mentioned, you take the blame as well. The big decisions will be tied to the store manager but yours jobs are mostly paralleled.