Do I have a stress fracture?

I am planning on going to the doctor tomorrow, but I just wanted some insight. For the last month or so I have had mild pain in my foot (in the outside middle of my left foot) mainly in the bony area, but it sometimes hurts in the fleshy part of my heel. Some days the pain is worse than others and it hurts the most and is very stiff when i wake up in the morning. I work a job where I stand all day would standing too much cause this? I don't think it is my shoes since it is only one foot and it does not seem to correspond with when I work. When I make a conscious effort to keep my weight on the other foot a notice a difference in the stiffness and pain the following day.