My foot hurts on the bottom right side. I can barely put any weight on it nor trying to move it at all. It has a consistent trobbing of pain whether I'm on it or not. Hurts when squeeze in a certain area.

My foot hurts on the bottom right side. I can barely put any weight on it nor trying to move it at all. It has a consistent trobbing of pain whether I'm on it or not. Hurts when squeeze in a certain area. What is the cause and how can I prevent it from happening again?