The answer is
I am a gas that you love
Hydrogen powers the sun, without which life on Earth could not exist. Who doesn't love that? It is also useful for many technological applications, for example it can be used to store energy and powers some cars, such as the Toyota Mirai.
Most commonly found up above
The sun, which is up above, has lots of it, although it is also quite common on earth (e.g., it is extracted from natural gas and oil). If it escapes into the air, due to its low molecular weight it will rise up to the upper parts of the atmosphere.
I have no hues
Hydrogen is colorless
and convert into twos
when you trap me and give me a shove
This refers to nuclear fusion, the reaction that powers the sun: two hydrogen nuclei (aka protons), when trapped in close proximity and given a lot of energy (a "shove"), fuse to form a deuterium atom (and some other things, which then proceed to do more things to complete the fusion reaction cycle, as described for example here). Deuterium is a hydrogen isotope with two protons in its nucleus, i.e., a "two".