Get X-ray done to rule out calcaneal spur, check your footwear which you are wearing regularly, wear and tear of footwear also causes pain in heel and foot.
Weight gain also causes such pain.
Next Steps
do stretches of calf and plantar fascia, icing 2-3 times a day to painful region, toe curling exercises. contrast bath ( hot 5 min - cold 2 min-hot 5 min)
Health Tips
do not do exercises in your own if pain persists see a physiotherapist for the detailed evaluation and treatment to prevent further damage.