the higgs field IS why we have mass. you're only remembering part of Einstein's equation. a potentially huge part is also momentum. without going into heisenberg's (fitting, considering OP's avatar, lol) uncertainty principle, suffice it to say all mass attributed to matter comes from the higg's field, modulated by momentum and change therein, and interacted with by gravity. your last sentence is actually a kind of chicken or the egg kind of situation. no one knows where gravity comes from or why it affects objects that have the property we call mass. gravity also affects spacetime itself, because we see that massless light is also affected indirectly (gravitational lensing). OT: i think it's a perfectly clever name for the mod!