What Causes Chronic Numbness In Right Index Finger Tip To Joint?

Hi ,my right index fingerfrom tip to the last joint on my hand has been numb for 6 month ,and my right big toe is exactly the same . my doctor doesnt know but done test for diabetes and all clear ,im awaiting an x ray of the spine ,what ever that will show ,i had an x ray of my hand but all clear.any ideas? Its in my right index finger now to.