It used to only be strangers she would growl at or one of the other dogs if they got close to her food dish. Now she is growling at my son and the other dogs if they get close to her when she doesn't initiate it. Any ideas?

Not sure about age or breed but growling can mean several things. She could be afraid. Does she do anything else to give you a clue like humping or are there any chages in your household like a new person? Most dogs can be trained to not show or have this behavior, hold is she and have you considered obedience training?