That you're using a MOUSE, any mouse, might be the problem.
You might try a trackball?
I do programming and (ahem) a lot of surfing and I've never been more comfortable than with this
Kensington unit. It has a huge, hefty, easy-to-slide ball. (On the contrary, I've used many other versions of trackballs and found some annoying, others painful, even Kensington's other "Orbit" trackball. Usually the pain comes from havng to rack my fingers back & up to to move the ball.)
You gotta use what fits
your hand best. I have big hands, so this works best for me. YMMV.
And Kensington makes a wireless version too, BTW.
Image of the trackball
here.
Oh yeah, and FWIW I absolutely never use those extra keys or the scroll wheel. I should have just gotten the standard version.
[edit]Oh, not that I'm a guru though... /ubbthreads/images/graemlins/rolleyes.gif
[edit]Removed image tag after reading Sasha's note in admin pages that it's a bad thing to link an image from someone else's site. I'm sorry Sasha! <