Matthew Sockolov describes restlessness and worry and their relationship to getting lost in the thinking mind. Those thoughts often focus on things we have no control over. The post describes several ways of relating to restlessness and worry, including the practice of mindfulness of our thoughts. You can find his article here: Letting go of Worry
Gil Fronsdal has a good discussion of restlessness and worry, and looks at both physical and mental restlessness, and worry about the past and future. He looks at some of the causes of restlessness and worry and discusses several ways of investigating them and relating to them. You can find his article here: The Hindrance of Restlessness