Why do I get headache whenever I read something on a moving vehicle, while others don't?

not sure but its normal

It’s actually a pretty common problem for a lot of people. They say it’s bad to read while in a vehicle because of the uneven surface of the road and the way it interferes with the smoothness of the motion of reading; bumps and potholes in the road cause the words and lines to jump, making your eyes do double time to read, in turn stressing the brain more than it’s trained to experience when reading. Your eyes can’t focus well enough and you become dizzy- or in your case, get a headache.

Head aches could be case of bad eyesight. My sister had to get glasses and didn’t even know she had bad eyesight before that, because she was so used to the level of blurriness. She thought everyone saw that way. But she always got head aches while reading a book in the moving car (kind of similar to your problem). You should get your eyes checked, but this doesn’t automatically mean you need glasses. I get stomach aches when reading in the car, so I just don’t do it. My vision happens to be 20/20 and the stomach aches happen because your brain registers motion while you’re sitting down. That confuses it, thinking you’re sick and need to throw up. Maybe the print is too small also. Whatever it is, just avoid reading words off moving cars.