With age, gravity tends to give us a larger foot size. Our feet expand under our weight. Solid, well-made leather shoes can be stretched between a half-size to a whole size. Poor quality shoes can not take the stress of stretching – either the leather itself, or the stitching, will break.
Things to try: Shoe stretchers will adjust width or length. Cheap on Amazon. Over a day or two, you keep increasing the tension in the stretcher. Heating the shoes with a hair dryer or in a hot sun makes the leather a bit more stretchable. Soaking the shoe well with water or, better, isopropyl alcohol (rubbing alcohol) before stretching is what expert cobblers do. Simpler, soak with water or rubbing alcohol and wear the shoes. Be careful not to overdo it or you can end up with loose shoes.
An interesting ‘hack’ here suggests filling a plastic bag with water and placing it inside the shoe then freezing it/them. As the ice expands it will stretch the shoe. I guess this would work. We probably all have a box of ill-fitting shoes somewhere that we could experiment with. Might save a few bucks: http://www.lifehack.org/articles/lifestyle/how-stretch-shoes-that-are-too-tight.html