is it OK to include own questions on CV?
Ignoring exactly where you would put questions (e.g., CV or SoP), your example questions are inappropriate everywhere. They are such broad, unanswerable questions that they tell the reader little about you. The combination of questions makes the already broad even worse. If you are going to put questions/topics that interest you, they need to be specific enough, and ideally well thought out enough that they tell something abut you.

Instead of "how do we learn", maybe something like "in associative learning how does the saliency of the unconditional stimulus affect learning outcomes", if that is what you are interested in.