Thanks ladies for all the input. I bought the Dr. Sholl gel pads today (the ones just for the balls of the feet, since the shoes are pretty snug and I doubt a full insert would fit well) and will give them a try.
I do think it's not the heel itself (it's 2 inches, which is my maximum but I wear that heel height quite often) but this specific shoe. It's just not cushioned at all and it gets quite uncomfortable after a while. While I don't plan to wear these booties for extended walking, I would like to continue wearing them for work, and I've noticed that the balls of my feet start aching in the afternoon. Not good. I've never experienced this, my feet are generally pretty mellow. And of course these are my cute booties that I bought in Germany, so I'll neither return them nor will I swear off wearing them altogether. (I will, however, be even more picky in the future when buying shoes! I certainly hate the notion of suffering for beauty's sake.) I'll try the gel pads and hope they can turn them into 8 hour work day shoes; otherwise I'll have to wear them for evening occasions where I'll be sitting more than moving around and/or just only wear them for a few hours at a time.