It may not be a bad thing. A lot of company's try to cross-train their employee's to be able to do more. Or maybe to see where you are a better fit. I wouldn't worry unless there's something more going on. Then I may ask the manager "why the change?" Hope this helps :)
Your Manager has decided to transfer you to a different department in the store where you haven't worked before. How would you view this change?
A good thing. You can gain new experiences learn new things which can lead onto better jobs in the future :)