mirroring wiggle with a pin

Your question is a bit unclear, but that's a technique might be useful to you:

Outsource the wiggle and apply it everywhere you need it.

To do so, create a null object and put it on position [0,0]. Add the wiggle on this null.

The wiggle will take the position, calcuated the wiggle and return position + wiggle value. Since position is 0, you get the pure wiggle value in return.

Now on your pin, you add this expression:

    wiggle = thisComp.layer("Null").transform.position;

    value + wiggle;

If you need wiggle's individual x and y values, you can access them by:

    wX = wiggle[0];

    wY = wiggle[1];

    // the same applies for 3D layers: wZ = wiggle[2];

And if you want to change values, you can do, for example:

// change sign: +4 -> -4

invertedWiggle = wiggle*-1;

// change directions x -> y

reversedXY = [w[1], w[0]];

value + reversedXY;

// invertd and change directions +x -> -y

invertedReverse = reversedXY*-1

value + invertedReverse

and so on ...

If you don't want to add another layer to your comp, you can also add a 2D or 3D point controll effect and apply the wiggle on it. Just make sure the standard values are all 0.

Then you pickwhip the point control as wiggle and all the rest stays the same.

*Martin

Without an understanding of your setup nobody can advise specifically. Show us a screenshot and explain what needs to go where.

Mylenium

you can always add 

* -1

to your expression to get a negative value, but maybe you will face an issue with the position parameter so your object will go outside the screen, any way you can fix that by using transform effects and set the position where you want it