There are times that I have to work from 7am to 3pm then come back that same night at 10pm and work until 6am what is utah law for the pay of this.

Depends on what day/time the employer has designated as the beginning of the workweek. They have to designate one. However, Utah only requires compliance with federal law, which mandates overtime pay for nonexempt employees only if you work over 40 hours in the workweek; there is no daily overtime requirement.