I have oa in my instep. painful burning pain in big, + middle toe, instep after removing shoes/when crossing my leg or upon rising till i walk awhile.

Pain : See a good podiatrist as he may be able to fit the you with inserts to reduce the pressure. You also would benefit from a course of anti inflammatory drugs

Orthotics: Midfoot OA is difficult to treat. There are no good surgical interventions. But orthotics with good midfoot arch support can help. I usually recommend the inexpensive over the counter version until your foot gets used to the feeling. Later the custom orthotics can be made if you like the added support.