What Causes Numbness And Pain On The Foot After Walking And Standing?

I am almost 60 years old and have had gradually increasing pain in the ball joint area of my left foot. I now have some numbness on the top of the foot in that area, extending to part of my middle toe. Being on my feet, whether standing or walking, for a long period of time will result in a miserable evening. At that point, it really, really hurts to touch it, but there is no redness or swelling in that area. I work at a desk all day and the process of being up and down is unbearable most days. Once I ve been up and walking around some, as in the grocery store, etc., it gets easier to walk without a limp. But, the end of the day, once I ve been able to sit down after cooking, etc., throbbing sets in. Some days are worse than others, but I haven;t been able to pinpoint why. Going to sleep is tough most times, as my foot throbs - many times I also experience a stabbing pain along with the dull achiness in that area. X-rays at the doctor s office showed nothing - doc suspects arthritis, but it s nothing like the arthritis I have in my fingers.