But I do think that whenever energy is drawn upon itself, when orbits are entered and achieved, mass comes into play.
The greater the amount of enery bound in circular motion, the greater the mass and the greater space/time distortion. I see phontons as a quantive unit of force rather than an actual particle. And there is no discrepancy that a units of force can't propogate as a wave.
Were all matter played upon an infinite mass, (which in fact would be a singularity), energy would be propogating in a medium not much unlike a superconductor.
This is what happened to Newtonian mechanics, and resulted in Einstein's theory. At "normal" velocities, its' answers are equivalent to Newton's. Since Newton's equations are easier to use, it is more common to use them for "everyday" applications. Mechanical engineering is one example.