Why didn't we have inflation when the theory of everything and GUTS broke symmetry? I asked this in astronomy and they suggested I ask it here. Inflation seems to have occurred when the symmetry breaking of the electroweak occurred. But do we know of any reason why we did not have inflation when gravity separated from the other forces or the strong and electroweak separated? Are all these other symmetry breakings associated with the Higgs field and a mexican hat energy distribution. Sorry it is all a bit confusing.
 A: Inflation, separation of gravity from other forces, separation of strong from electroweak force, and electroweak symmetry breaking, are all different events. 
It's easiest to start by describing the different sorts of fields involved. Quantum fields get classified by their "spin", which describes the angular momentum states that field quanta (particles) can have. Gravity is spin-2, the other forces (gauge fields) are spin-1, the Higgs and other scalars are spin-0. (And quarks, electrons, etc are spin-1/2.) 
The unification of the forces describes by gauge fields - electromagnetism, weak, and strong - is more straightforward than unification with gravity as well. Gauge fields are described by Lie groups, a type of symmetry groups. A unification theory may have a single gauge field with a big symmetry group containing lesser symmetries. Interaction with Higgs fields can give mass to many of the components of the big gauge field, with the remaining massless or low-mass parts only exhibiting the lesser symmetries. 
Electroweak symmetry breaking is an example of this... a full symmetry of SU(2) x U(1) is broken by a Higgs field so that just a U(1) part remains massless; that gives us the photon; while the other, massive parts are W+, W-, and Z bosons. 
In a larger unified theory like SU(5), the full gauge field is an SU(5) field, which then gets broken by some superheavy Higgs fields to an SU(3) part and an SU(2) x U(1) part, and then the latter gets broken to U(1) by the light Higgs that we have now observed. 
In that sort of theory, in the early universe, there is a "grand unified" stage where all parts of the SU(5) field are still massless, then there's a first symmetry breaking by the superheavy Higgs fields, and then the second, electroweak symmetry breaking by the light Higgs. 
So maybe it's important to understand that in the standard model, which has symmetry group SU(3) x SU(2) x U(1), there is indeed only one Higgs, "the" Higgs. But a Higgs field is actually just a type of field, and in a grand unified theory like SU(5), there have to be other, heavier Higgs fields, to cause that first symmetry-breaking that breaks the SU(5) symmetry. 
Inflation, and unification with gravity, belong to an earlier stage and to even higher energies. 
Since is gravity is spin-2, it can't be unified in the same way. Before string theory, the common idea was extra dimensions. If you have gravity in a space of many dimensions, but make some of them "compact" so that e.g. only three spatial dimensions are large, then the components of the gravitational field which pertain to attraction in the extra dimensions, show up as spin-1 and spin-0 fields in the three large dimensions. 
Meanwhile, the idea of inflation is that the energy in some scalar field, the inflaton field, causes an accelerated expansion of the universe. There are models in which the electroweak Higgs or a grand unified Higgs is the inflaton, but normally, the inflaton is thought to be just some other field entirely. 
If the gauge field forces do derive from higher-dimensional gravity, then it is possible that only three of the dimensions inflated, and that the separation of gravity from the other forces occurred then. But again, the concept of inflation is a general one, and that would be just one very specific theory about the real-world details. 
