Twisting, knotting pain when bending over.

Due to the location of your discomfort, a second possibility might be an issue with
your bile duct
your liver 
your gall bladder or possibly
your pancreas (though less likely).

All of the above are potentially serious (though often only after prolonged problems).

Certainly your GP will be able to help.

This should not be anything realted to WLS - probablyseparate issue.

That sounds like a hernia to me.. just cuz of your saying you can feel it and are able to rub it or give pressure and it goes away.
Hernias are not uncommon with WLS