The first time I used these, I had to cut my usual walk short, as they actually seemed to CAUSE PAIN in my feet. MUCH worse than my usual achy feet. Both of my feet were REALLY sore in the middle/arch area, and my left foot was getting a shooting pain on the side that I have never experienced before. I took them off when I got home and was fine the rest of the day. Against my better judgement, I tried them again the next day in a different shoe, thinking I just need to "get used to them." Boy, was I wrong...again I had to cut my walk short because my feet were KILLING me, and significantly increased back pain! This time when I took them off, the pain did not go away. My feet and back hurt the entire rest of the day. On day three, I did NOT try them again, but instead returned them. The front and back (toe and heel) sections of the insole are soft and cushy to the touch, but the center (arch) part of it is made out of a hard plastic, and I am assuming this is the culprit for the pain.