I Have Been Having Severe Foot Pain About Once Every 6 Months. What Could Be The Reason Is?

severe foot pain about once every 6months, used RICE but no help. I have been having severe foot pain about once every 6months. it starts out as mild and then gets to the point were i cant walk and even touching the foot hurts alot. I have went to the doctor before and besides swelling nothing really shows on x-ray. The pain is pretty much originating at the balls of my feet, and usually by the small toe. I have tried, tylenol , advil , and prescribed vicodin but none of them seem to effect the pain in any way. Only once by taking 3x the normal dose of advil did the pain seam to go away. I have used RICE (rest, ice, compression, elevation) to little or no effect. It seams just a few days after the worst pain sets in it starts to go away on its own if i dont trip over anything.