If an unopened bag of ground coffee is very inflated, does it indicate a problem with the coffee?
If the coffee is, (ground or not) sealed directly after roasting, the coffee will still gas out, releasing CO2 as a result from the roasting process wich leads to inflated bags. On many coffee bags, especially from "smaller" roasters there is a little valve integrated to let this excess CO2 escape rahter than blow up the bag. This happens for up to two weeks after roasting, the most of it shortly after.
It is rather a sign of freshness, but that depends on where you got your coffee so I can only speculate if it is fresh and that that is the cause ;-)