thanks for writing to HCM,
From your description it seems to be a soft tissue injury
as your X-ray is clear. it may be tendinitis
or a ligament sprain
this can be cleared by doing a clinical examination by a orthopedic/ physiotherapist. Also a MRI
scan of the ankle can bring out all the details.
This pain can be related to your tight plantar fascia as it will put pressure on the neighbouring structures.
For this intense pain you can take the help of your physiotherapist.
i hope this helps
wish you good health