A sudden flash of warmth comes & goes for 1-2 secs under my right foot since a week. im 39 yrs old, 7 kids: breastfeeding a 4 month old ?

Flash dance step..: Flashes of warmth, lasting for seconds, are usually due to a nerve inflammation . In your case , the nerve is located in the bottom of the foot. Depending on the area of the warmth it could involve a nerve in the ankle. Perhaps a straining of the arch area causing a stretching of the tissues on the bottom of the foot. To remove all doubt, have your foot examined by a specialist.