“If you are distressed by anything external, the pain is not due to the thing itself but to your own estimate of it; and this you have the power to revoke at any moment.”  Marcus Aurelius.

Then is all pain not initiated externally, save for guilt, shame and remorse? and then even those may be brought forth as the result of other acts.

So how does one revoke their estimate of the significance of that which causes them pain?

Or is it greatly more about the response to those things in life which test us and pain us. We can control our response. Perhaps a re-evaluation of how one handles pain is the more effective, a means of measuring their strength, as opposed to estimating the significance of that which pained you and not measuring your capacity to forge ahead productively and peacefully, there in is a challenge.