How many times have you heard that? It's obviously referring to some song—and it's usually, usually a song that you don't really like all that much. I mean, if it were, the phrase "stuck in your head" wouldn't have a negative connotation.
There are a couple of other connotations I'd like to explore.
In the book of Joshua (1:8), he is commanded by God to "meditate" upon, or think about God's word "day and night". This means so much more than simply memorizing it and having instant and total recall. I heard a comment a long time ago: "the Word you memorize is the Word you utilize" and I agree with it only up to a certain point. When all we do is have it stuck in our head, and we don't meditate on it as it says in Joshua, then we may not end up utilizing it—at least not correctly. The psalmist said "Thy word have I hid in mine heart that I might not sin against Thee" (119:11). Heart supersedes head.
One day several years ago I met a man who stopped me and asked me if I'd seen a young man—a teenager—that he was looking for. I told him no, no I hadn't. He proceeded to tell me (he was visibly angry) that the young man in question was his son and that, earlier that morning he had cussed out his mother and then punched his sister and then left. I was shocked. And I was sure I'd not seen anyone that fit that description. He thanked me and continued his search. I went on my way. I saw that same man the next year and he stopped me again. And told me the same story. Though when he described the ages of his children, they were younger than last year. At that moment, very gently, the slightest of realizations dawned in me. I thought to myself, this man is certifiably crazy. Though today I'm more inclined to think he is simply stuck in his head.
I suppose those both have negative connotations. Then how does someone, anyone, move from head to heart? The process is as simple as getting God involved. Bible study is something that can be done with or without God. But the things like prayer, gratitude, worship and praise necessarily involve Him. This is where, the more of the word of God that you have memorized, you'll certainly utilize. Or should I say, the Holy Spirit will utilize through you? Paul wrote that "the things of the Sprit of God...are spiritually discerned" (1 Corinthians 2:14).
The concept of a "concrete head"—someone who is thoroughly mixed and permanently set—certainly applies to those who are stuck—in their head. And as we live from our heart, not worrying about accruing a bunch of knowledge and information, God will effectively shift our focus and unravel the mental blocks that we have.