They can be, but not always. 'Put away' means to put something where it belongs ie its storage place. 'Put back' means to return something to where you found it. Let's say there's new jar of jam on the kitchen table at breakfast time. Your mum has just been shopping and put it straight onto the table. You pick it up and take some jam for your breakfast. Then what do you do? Do you put it back on the table? (Which is where you found it) . Or do you put it away in the cupboard? (Which is where is needs to be stored). I hope that makes sense.