I think one of the main reasons you’re getting some type of “motion sickness” is due to the graphic quality of the game. I am bumuming you got Fallout 3 for the PC, and if you were able to play it on the PC, then your graphics card must be pretty good.

Being a console gamer and having Fallout 3 for the Xbox 360, the graphics are pretty sharp and clean. Personally, my eyes start to hurt if graphics on a TV or a Monitor are ultra sharp because I don’t really know what to look at, it’s all shining at my eyes. Also, I’m not sure if Fallout 3 has this since it’s been awhile, but it may have some sort of debris effect (random debris falling from the sky). This might add to your “motion sickness”.

All in all, you should probably get used to it, and if it’s from your PC, then I’d sit farther back. Like I said, being a console gamer, even though the graphics are very slick, I’m still like 2-3 feet away from the TV so you can take it all in.

Thus, simple sentence should sum this all up:

Fallout 3’s graphics are too damn good; this is why your eyes are hurting.