Trust me you need to get an orthotic insole. I was running 3 miles a day and ignoring my pain that it caused me leg. Before I knew it I had to come home from the Marines to have knee surgery. Mine were expensive but insurance paid for most of it. On top of that, I believe certain stores cell "custom" but not really custom ortho inserts. Don't just get the arch support you need to get something a little more serious.
Whatever you do it will be cheaper than surgery down the line.