cannot say what in your particular case without direct examination. But I can say everything that is in the foot includes bones, joints, tendons, circulation, and muscle. WIth a lot of pressure there can be stress fractures of the bone. They give intense, constant pain. The joints and tendons can get strained. This occurs most in the part of the foot with the most bend (the middle at the top or in the arch). This area goes up and down in pain during the day. It goes up with use, It hurts when that part is bent etiher by flexing the foot or by directly moving that area. Muscle can hurt; they have a particular muscle ache. There are not prominent muscles in the top middle of the foot, more joints and tendons. Circulation can make the whole foot ache and there has to be signs of poor circulation. The pain comes either with use, with blue swelling, or with lack of blood, being pale/white/cold and achy with use but would be the whole foot (really really doubtful in this case). Joints and tendons are helped with changes in shoes and activity, wtih aspirin like drugs, and rest with gradual buiding up use with physical therapy.