Suggest Treatment For Recurring Pain In The Sole

I have had recurring foot pain in the last week and a half. The pain is on the bottom of my right foot, the sole, and it goes off and on. Right not I think it might be swelling because there are some parts that I can poke and it hurts a lot. I also can't walk on it right now. But even when I can, I have to limp or walk on the side of that foot. What is it?