I bought a new pair of trainers as my old ones had had it. I had to buy online and couldn’t try them on like I’d usually do. They seemed to be fine when I first wore them, so I cut the labels off and have been wearing them every day since Saturday. However, my heels are now in agony as the backs of the shoes are so tight and stiff. I’ve actually retrieved my old ones from the wheelie bin. Will they gradually soften over time? Is there a way to help them along? Or are these just the wrong shoes for me?