See a decent physio. Do a decent rehab programme. If you and your therapist are happy you have addressed all that can be addressed from that side of things and you still have problems you may need to have an orthopaedic assessment with an experienced foot and ankle radiologist analysing your images.

I work with high levels sportspeople and I always get ankles/feet checked out if they aren't responding at 6-8 weeks of treatment. It could be a case of something less common but very troublesome like ruptured interosseous or bifurcate ligaments of the foot or indeed a peroneal tendon problem eg "splitting" etc.