I love this design and have worn it previously, but after wearing them for an hour or more, the bottom of both feet start to sting and burn and are painful. I don't know what to do about it. They are a size 9 and all of my other shoes are size 9, but am wondering if I need a larger size. Is it possible that my feet are trying to adjust to new shoes? I haven't worn the Terradora Ethos pair in case I need something different with them also. I ordered these on line, and unfortunately I don't have the shipping papers.