I think a lot of RSI is related to holding tension in your body.

The more direct physical way to "fix" it is to adopt a neutral stance with your body. Let your arms hang down neutrally at your sides without using your shoulders to hold them up. Let your wrists be supported in a good position so the strings and pulleys from your forearms to your fingers function well. Support them off the sharp and low edges of the desk at a good temperature. Let your head be balanced over your neck and shoulders instead of holding it in position with your back and head muscles.

The way to exacerbate the problem is the power through it like a new runner with shitty shoes. Ignore all of it, hold tension in your neck and back and ignore the signals your body is sending. Keep your monitor off-axis. Use a shitty mouse and keyboard. Sit at a laptop for hours and get-er-done in spite of terrible ergonomics. (Do you know there are no OSHA approved laptops?)

The exacerbate case ignores your mind-body connection.

Now, it's not "all in your head" but your head is part of the problem.