Get a X-ray done and take pain killers for the same. Pain may be due to spur or plantar fascitis. If it's not improving with medicines and other conservative measures, you can get lithotripsy done. It's a machine which can break the spur and also help in plantar fascitis. The machine is available here and it's results are good.

Yours is a classical case of plantar fascitis, I would suggest you to take some analgesics, and change of footwear to soft sole ones, or silicon inserts in shoes. In addition to that there are some stretching exercises you can try out with the help of Physio. Also an x-ray will be helpful, to check for bony spur if any.