I Have Extreme Pain In My Left Foot. There Is

I have extreme pain in my left foot. There is no swelling and the pain is toward the outer part of the foot and hurts when I walk on it. It lessens a bit as I walk, but can get worse if I am walking or standing for extended periods. Even when I sit for extended periods and then get up to walk there is a lit of pain. Started about a month ago and has not gotten better. Could this be a stress fracture in my foot even if there is no swelling or would it be a different problem?