Typically, back (retroactive) child support is included (or not) in the original order for ongoing (current) support.
Back (or retroactive) support is typically awarded (or not) with the entry of the first order for current support.
It depends on the statute of limitations in the state where the action was filed.
She is entitled to child support regardless of where either of you live. It is your child and you must help support him/ her, and no, she does not have to move back to Nevada.
Once should be enough. "Back" (retroactive) child support is typically awarded (or not) with the entry of the first order for current (ongoing) support.
If by "back pay" you mean retroactive support, that is typically awarded with the entry of the original order for current support,
If the mother filed for it, and if the judge approves a retroactive order.
There may be regulations regarding any access to a person's disability check.
what if your done with current child support but still owe interest for back support.
A back order is an order which cannot be currently filed or shipped, but is requested for when the item becomes available.
That completely depends on your state of residence (or country if not in the USA) and the age of majority for that location. All states have statutes of limitations outlining how long a parent has to file for and recover any back child support if an order wasn't filed when the child was a minor. If such an order was filed, then yes, the father may direct the child support enforcement agency in his state of residence to collect any support in arrears.
You can not get child support for the previous year if there is a filed court document stating that you agreed not to get any. The best you can do is file for a change so that child support might be able to start, but it would not be retroactive.
If you filed the restraining order, you can withdraw it. You must go back to the court where you filed the restraining order and ask that it be dropped.