In my experience, thinking hard doesn’t hurt my head directly. However, trying to think hard under stress and sleep loss does. Whenever I noticed my head hurts trying to “think hard”, it’s usually a symptom that something else is going wrong.
Mew
Karma: 16
If you want to get a feel of the mechanics, I recommend Gilbert Strang’s Linear Algebra over Khan Academy and Brilliant.
I think part of the 3b1b series is based on that book and they have similar structures. Just sit down for 1-2 hours with some graph papers + mechanical pencil and do the end-of-chapter exercises, they are designed to reinforce the concepts.