Why does the bottom of my foot hurt?

I enjoy power walking as exercise. I’ve done it semi-regularly for decades.

I took some time off recently, and since I restarted, the bottom of my right foot has become sore around the arch. I wear good shoes.

I’ve had to stop the exercise altogether due to the pain. It’s very sensitive to touch, and it almost has a burning sensation.

Can anyone give me a clue what this could be so that I know what to tell my doctor when I call him?