Is there is secure Parking lot

No

I typically park in Pershing Square and enter on the hill street side. By secure do you mean is there security? If so then Pershing square is staffed with security guards. I've been parking there everyday for the past two years when going to the gym and going to work and have never had an issue.

There is a commercial parking garage across the street and some metered street parking.

Yes, multiple parking garages locally.

You're DTLA, you have to park in one of those toll parking lots