My question involves name change laws in the State of: California and Alaska

How do I find out what my legal name is? My last name was changed on my Social Security card as a child when my mother remarried. I've gone by that surname all of my remaining childhood and through all of my adulthood. In California, I never had a problem. I obtained a Driver's License at 16 with a letter from my school stating that I was going by the name on my Social and not my Birth Certificate.

I now live in Alaska and they won't issue me identification because my birth certificate and my social don't match. The do not accept letters from schools up here, it has to be a legal document. I have called the local courthouse where I grew up and there's no record of a name change. I tried calling Social Security but the automated system said to call later in the week because they were too busy. My California ID is now expired and I have no legal identification and don't have time to sit and wait. I don't even know that Social Security can offer proof of a name change. Is there someone else I should be calling? Is it possible my legal name is still my birth name?