When I bend my foot to the left I get a sharp pain on the right about where the arch is. I do not have a low arch or a high arch. I have not fallen recently on that foot. Sometimes when I am walking through the school then it starts to hurt. What is it and what should I do?

No one who isn't examining your foot can know what it is. There are too many nerves that could be irritated, there could be a bone chip or spur, there could be a sprain or interior bruise pressing on a nerve - just about anything.
Doctors usually tell you to soak in hot water (ice if swollen first), keep it elevated, take Tylenol, and wait. Then if it doesn't get better, they might do an x-ray. But x-rays will only see something wrong with a bone, and many times the reason isn't found without much more testing, and it goes away by then.