How Can Calf Pains And Numbness Due To Being Flatfooted Be Treated?

Hello I am 54 and a runner. For 8 months I have been having leg pains in my calf which causes slight numbness when standing for an extended periods of time. I have no pain while sitting. Also, I am flatfooted which I feel may contribute. I used to run hard pavement frequently, but I have ceased doing so within the last year. Any possible advice