I think you have already been offered some really useful adivce, especially the last comments. However, it is very difficult to assess the problem without a physical examination. I feel many GP's do not have the necessary sports science knowledge to understand how activity can impact on the body, therefore you need a specialist to offer you further guidance and you should ask your GP to signpost you appropriately. You do not state whether or not during your dancing career you have danced on blocks, if so what type of protection you have used. For example the new Hi density cushioned overlay or old fashioned animal wool and surgical spirit. It is difficult to assess what shape your arches were in prior to dancing. Other factors such as congenital conditions or genetics may play their part in this. It would be advisable for you to look at the shoes you wear each day. Do they offer support and are they a sutiable shape for your feet? Wearing appropriate footwear dependant on your activity is essential. Many Universities, which have a podiatry department will have students who would love you as a patient. You could access a bio-mechanical assessment and gait analysis, which would help to diagnose what the issue is and how best to treat it. In the meantime try some reflexology with a good therapist and try some exercises to see if working your pressure points helps. Good luck with eveything.
Elizabeth Farrow BSchttp://www.colorpurpletherapies.com