Is it correct in saying that a particles size is it's rest energy, and that particles don't actually have size (in the way you get different size objects)?

What defines what sizes a particle can be? Why do particles have discrete sizes, and there's not a continuous spectrum of particles varying in size?

I ask because I was told that particles mass depends on its size, as the bigger a particle is the more it interacts with the Higgs boson and so the more mass it has. So why are there so few particles with specific masses/sizes?

In pair production, the amount of energy put in determines the particles that are produced, how is the energy required so definite, why do some particles need more energy than others and vice versa to be created?

Is it correct in saying that a particles size is it's rest energy, and that particles don't actually have size (in the way you get different size objects)?

What defines what sizes a particle can be? Why do particles have discrete sizes, and there's not a continuous spectrum of particles varying in size?

I ask because I was told that particles mass depends on its size, as the bigger a particle is the more it interacts with the Higgs boson and so the more mass it has. So why are there so few particles with specific masses/sizes?