Oddly enough, dreaming of a colleague rarely involves issues at work.
The focus is more likely to be on traits this person possesses that mean something to you.
For example, if this person’s voice is especially loud, whatever he or she is saying to you in the dream is especially significant, and you should pay attention.
If this person is someone you feel you can trust, there is some issue in your life involving trust that needs to be resolved.
If you dream that a coworker whom you don’t particularly like suddenly acts like your best friend, or a colleague whom you like and respect turns hostile, be prepared for a reversal of some kind - for better or worse.