Which hand do fighter pilots use for the control stick?
Most fighter pilots, regardless of their handedness, use their right hand to fly the stick, and their left hand to move the throttle(s)/PCL (Power Control Lever). This is just how most fighter cockpits are set up, with the power on the left side.

The sticks are also not really usable for a left hander because a few of the buttons would be inaccessible with a left hand on the stick. In some cases (like the F-16), the cockpit uses a sidestick layout, with the stick on the edge of the cockpit, rather than in between the pilot's legs.

So no, it would not really be possible for left-handed pilots to fly with their left hand on the stick for long periods of time (I will note, that if you need to select something on the right side, most will hold the stick lightly in their left hand for a brief second, actuate the item with their right hand, and then switch back) unless the entire cockpit were redesigned, which is just not worth it.