What is your idea of creation or destruction of mass ? The way you have explained above , it is basically conversion of mass into energy following Einstein's Equation e=mc*c ; than destruction of mass .
It is fairly certain that during thermonuclear reactions, mass is lost, released as energy that cannot be measured as mass. When I used the word destroyed, it was perhaps a bit absolute. I did however, qualify that by associating that destruction with a conversion to, or release of energy.., that is not directly associated with mass.
At least a part of the issue here is that while as we currently understand mass and energy, we can say that mass has at least a component that is energy. We cannot say that all energy has mass or can be transformed into mass.
To clarify this last point, while we can also say today with some certainty, that inertial mass, gravitational mass and rest mass are all equivalent.., the same. We can also say with certainty that the relative velocity of any mass does not have any effect on its grabitational mass. Which establishes that, at least with respect to the kinetic energy associated with an object's velocity, the involved kinetic energy does not contribute to an object's mass, inertial, grabitational or rest mass. And yes it does contribute to an object's relative momentum, which is sometimes confused with mass.
Perhaps you are talking about photoelectric effect where photons are generated from energy .
The photoelectric effect is most certainly, at least part, if not in some interpretaions wholly the mechanism involved. The details of this remains largely theoretical. It is very difficult to actually measure the initial and final mass involved, even in controlled reactors the actual mass/energy conversion is small, by comparrison to the limitations necessisary for containment and measurement.
In other words, you could weigh nuclear material before and after use in a reactor, but it would be near impossible to determine any loss of mass resulting from the cooling process required in such reactors and then compare that to any accurate direct measurement of the EM radiation (photons) involved.
But this happens as per Einstein's Equation . So, all the mass are accounted . Where is the unaccounted mass that we can call it 'destruction of mass' ?
This is really the point, the equation we are discussing accounts for the total energy involved in such a way we can say with some certainty that energy is conserved, but as an atom's mass is diminished by the emmission of a photon, which has no independent rest mass, and which may never be reintegrated as mass.., as in absorbed by another atom, we cannot say that mass itself is conserved. Mass is conserved only where each photon is reabsorbed by another atom.
Ideally, if you have a closed system, where no photon escapes without being reabsorbed, you could hypothesize that both mass and energy are independently conserved. We cannot say with certainty that the universe is a closed system, though some of our theories suggest that it may be.
If even one photon has been emitted from an atom, that has not yet been absorbed by another atom, the total mass is not conserved while the total energy is.
So, assuming the conditions established by the big bang theory, are there any photons today, left over from emission events in the past which have not and may not ever, be absorbed.., interact with another atom?