I received a lien notes for back child support on my IRA account. I live in California. How do I get child support to take the lien off my retirement account ,and can they take my IRA money while I'm paying child support?

The lien cannot be removed until the arrears are paid, including interest penalties. Why are you in arrears? Did you have a period of unemployment and you didn't file for a reduction. Legal representation for that was free from the state. Depending on the state you live in, if there was a valid reason for not paying the full amount, the option may exist to request a reduction.