He has our son and won't let me have him back. What laws are there were I go get my son. Can I take a cop to go get my son?

Yes, there are laws to be put in place by a trial judge to determine time and when and where you both can have your son. This has to be the biggest downside of divorce with children involved.

Why wasn't this done at your divorce proceedings. That's usually the time to figure all of this out.

Has anything been court ordered as part of the separation? If not, then you have equal rights and the police will not intervene. You need to get a court to set custody/visitation first.