To dream that you are trying to find something in your locker means that you are trying to fill the gap in your waking life, because there is something missing in it. If you are unable to find the thing you are looking for in this locker, it means that you have some troubles that are hard to be solved, however you will find solution to it shortly. If you are getting rid of the stuff that is in this locker, it means that you are changing your life completely. If you are unable to unlock your locker because the lock is broken, or you cant find the key, then it means that you lost control of your own life.
Read more about dreaming of Locker in other dream meanings interpretations.