Here's some info if flat feet might be playing a factor.

Arch supports take time to get used to. Especially if you have flat feet, they'll be uncomfortable and can even make your feet sore and tired faster to start (at least I've found), and if you go too long without wearing them you'll notice the transition back. They also take a bit of time to sink into the shoe and get comfy. You could try a softer support, or putting them under your normal insole that comes with your shoe. If you foot has a tendency to go flat in the arch when you push down on it, you may be compensating without thinking about it by flexing your toes and foot to keep your arch up.