A Bunion (excess or misaligned bone in the joint) is one of the most common big toe problems. In addition to causing pain, a bunion changes the shape of your foot, making it harder to find shoes that fit. Bunions usually occur at the base of the big toe. They are often caused by incorrect foot mechanics. The foot may flatten too much, forcing the toe joint to move beyond normal range. In some cases, joint damage caused by arthritis oran injury produces a bunion. Some people are just born with an extra bone near a toe joint.