N.D.
Double check his vision. My son seems to "squirm" mostly when he was focusing on objects close-up but his squirmy behaviors seemed to always be present. We just learned that he is very farsighted and so this behavior is a result of him being very irritated and not realizing it. There is a huge difference between his two eyes and what he can see and it turns out that this difference is what is causing his behaviors. Either way, I would have his vision checked out.
Hope this helps.
N.