My head feel heavy as I get older and slump more. What should I do?

Posture. Oftentimes, this may be a simple fix. As more people are using computers, the screen may be too far away from your eyes causing you to lean forward unnecessarily fatiguing your neck muscles. Simply moving the computer screen closer so that your head is resting more neutral on your neck and shoulders usually fixes the situation. If this does not correct, then i would get evaluated.