Do I need to report freelance work to the army?

By reg you are suppose to get permission from the CO

You profile doesn't say if you are active or reserve component. If active duty you should have your Commander's permission for employment outside of the Army. If you're reserve component, you probably don't need permission because it's expected reserve component Soldiers have civilian jobs.

At the least you should sit down with your Squad leader or Platoon Sgt to let them know and dispel any concerns.