Sudden foot pain and numbness on sole of foot. really painful, comes & goes over last 2 wks. not diabetic. what could it be?

Nerve: Most common causes are: herniated disk causing pressure on one of the nerves going to the foot (radiculopathy). Tarsal tunnel syndrome also can cause these kinds oif symptoms. See a neurologist or an orthopedic surgeon for evaluation.

Neuroma: Morton's neuroma, is the most likely cause of localized pain associated with numbness, in the balls of peoples feet. However, your kind of young to be developing this already. However, when you experience numbness, you got to think nerve tissue. Consult your local area podiatrist. This indeed can be a periodic observation.

Many possibilities: Foot pain could be as a result of many different things. A thorough history and physical exam and possibly some laboratory and radiology exams are needed to determine the exact cause. Causes of pain may include: trauma (fracture, sprain, arthritis), infection, metabolic conditions (gout), musculoskeletal or biomechanical abnormality and neurologic conditions (neuropathy). Have it evaluated.