Dazed and confused

Ok, so something's confusing me. Lately I've been trying to wrap my head around the idea that Jesus is "the son of God." What exactly does that mean? If you gave God a paternity test, would it come back positive? They have the same DNA? He wasn't even raised by God, he was raised by Mary and Joseph. And I'll bet he was quite a handful.

So in what sense, exactly, was Jesus God's son? Maybe the logic goes like this: I'm omnipotent, and I say he's my son, so that makes him my son. QED.

What's even more confusing to me is the idea of the Trinity. That God and Jesus are "of one being", along with the Holy Ghost. We usually refer to this sort of thing as split personality, and it's usually considered a problem.

Ok so I'm reading Verse and Voice from Sojourners today, and there's this quote from the bible.

As he was setting out on a journey, a man ran up and knelt before him, and asked him, "Good Teacher, what must I do to inherit eternal life?" Jesus said to him, "Why do you call me good? No one is good but God alone." - Mark 10:17-21

Wait. I thought Jesus and God were one being. But here's Jesus saying that no one is good but God. So Jesus apparently doesn't think of himself as being the same as God. Maybe when he was at least partially human he wasn't perfectly good precisely because he had taken on human form. Now that he's died and shed that body, he's just as good as God again?

This sort of thing makes my head hurt.