CRJ-700 pilot reported return to departure airport due to fuel imbalance and low fuel caution message.

Narrative

A fuel imbalance was noticed and we stopped to call maintenance to help diagnose and fix the imbalance issue. On the phone; Captain stated the fuel quantities in each tank multiple times. Maintenance assured us that the aircraft was normal and the condition of the fuel tanks were safe for flight. Once we took off the wings were balanced but the imbalance condition quickly returned resulting in a low fuel caution message for the left tank. We requested assistance and returned to ZZZ with no further issues.