numbness on right side of middle toe on right foot

For over a year the middle toe on my right foot has been bothering me.
After wearing shoes all day the toe is sensitive and causes discomfort (minor pain).
I tried wearing shoes with a larger “toe box” but this did not make any difference.
Within the past couple of months I noticed that while I still have this pain, the right side of the middle tow on my right foot is now numb.
The left side of the toe has feeling but the right side and end of the toe have very little feeling.
This numbness is continuous, even when I go barefooted at the beach for several days. My family doctor had no suggestions.
What could be causing my problem and what can I do or who should I see about it?