Janet,
I am sorry the soap trick did not work for you, but I suppose not everything will work for everybody.
Can't see how it could be wiggle room since the bar is placed under the fitted sheet.
I read a story on the internet that a lady put a bar of soap at the foot of the bed without tellng the hubby. The next morning his pain was better (I think that is how the story went) So, if the story was true than that shows it is not a placebo effect action.
Just my thoughts.
Blessings,
Dawn