The feet are complicated structures made up of twenty-six bones, which form two arches, one running the length of the foot and one running the width. When referring to arch pain, most people mean the long arch between the heel and the ball of the foot.
Pain in the arch of the foot can be the result of strain and inflammation. These can occur for a number of reasons: muscle strain from an injury, a physical formation of the foot that causes an imbalance, or strain to the plantar fascia. The plantar fascia is a tough, fibrous band of tissue that runs along the bottom of the foot, supporting the other ligaments and muscles of the foot; painful strain to this tissue is known as plantar fasciitis, and it’s the most common cause of arch pain.
The plantar fascia connects the heel bone to the toes, so it covers a large area. It can become strained as a result of being stretched too much; this happens regularly in people with over-pronated, or flat, feet. The way flat feet are structured pulls the tissue away from the heel, causing pain in both areas; wearing supportive or specialized footwear can help prevent and treat this. The pain from plantar fasciitis is generally at its worst in the morning, after a prolonged rest.
In some cases, arch pain may actually start elsewhere: tight or injured muscles in the foot can cause pain that leads you to overcompensate or change the way you walk or stand. This may have the unintended effect of straining the muscles in the heel or arch; properly stretching, resting, and treating pain or injury in other areas of the foot can help prevent injury to the arch.
People who are prone to arch pain or who have flat feet should take care when selecting their footwear: high heels should be avoided, and low-heeled or flat but supportive shoes favored. Insoles should be sturdy and provide sufficient padding and support; you can purchase more supportive insoles and replace the ones in your shoes, and people with flat feet can get orthotic inserts designed to cushion and shape the foot in the best way.