Thanks for posting your query.
From description it seems you might having soft tissue injury
or ligament injury
at foot as xray is normal and showing no any bony injury.
Generally it heals in one month duration if immediate icing and proper rest given to foot( rest, ice, compression and elevation).
I would suggest getting this evaluated by an orthopedician for an accurate diagnosis and appropriate management. You may get the MRI
of the area affected under his/her guidance.
Wishing you good health.
Dr Saurabh Gupta.