22 yr old with ankle pain

Boy preparing for army fitness test suddenly complains of pain in ankle. Pain s mainly in medial arch of both foot , more in right. On and off complain of pain in lower back also.
When  I examined him at pratiksha I could see foot in eversion with reduced arch.
Fine I prescribe him correct footware with customised insole but what about the pathology?
Will rest and anti inflammatory be a solution.
No the answer is treat the root cause
This requires coordination between physio, orthopaedician, prosthetics and the awareness of the root cause.
What u say is the root cause?