Not sure that I qualify to comment here but I will.
I am not really into causing a lot of pain so maybe I can help because it is a mental thing you are troubled by.

Pain is just not suited for great stress, it makes the stress worse because you lack the ability to relax enough to enjoy it.

When mine feels lost and can't find her sub or slave I give her little things to do that don't require much effort but give her a constant reminder that she is mine.

I know I have talked about in other threads but it doesn't ever seem to fail. I have her wear a skirt or dress without any panties, then I have her take a garter belt and tie silk ribbons every half inch across the front with small knots it them. These hang down to tease the thighs and clit as she moves, even seated a little movement and she feels me with her. I have been told that it is hard to stay stressed out during that period of constant reminders.