Kathleen, these sound like heel fissures - a form of callus - they are very common, especially in people over forty, or anyone who does a lot of standing on a hard surface. Wearing shoes or socks that don't fit well, being overweight, or having very dry skin can also contribute. Unless you have diabetes or vascular problems, they are generally a cosmetic problem, not a medical one. Soaking your feet to soften the calluses, and using a gentle pumice stone or pumice scrub, then an extra healing lotion will usually heal them up. You can also buy socks that have extra heel padding to protect your feet. Depending on how you sleep, you may also be putting pressure on your heels as you sleep - wearing heel protectors at night may help. You can also buy over the counter treatments - CalleX and Total Foot Recovery Cream are both good. If these treatments don't help, your shoes may be the problem so you might need to see a podiatrist.