I broke 1 main bone in left foot march 16th. foot still swells when i am up long. sore too! how long will this go on?

Time is on your side: It sounds like it is not sufficiently healed. The swelling is a sign your body is not satisfied with the bone strength. Some times these fractures take more time. Best to get an x-ray. It is not an emergency, so have the x-ray when you can. In the meantime, try to take it easy on it. Avoid stressing it. Sometimes moist heat will speed things up.