Hi,
i suffered from terrible foot pain for about three years before being diagnosed with lupus. I also had terrible joint pain. My feet would swell and ache all across the top and around the ankles. They would hurt so, until I would be limping around at work and it was noticeable to others.
Since lupus can cause arthritic like symptoms with your bones and joints, it is quit reasonable to think that it could cause problems with your feet. I used to soak them in a warm foot bath and then stay off of them in the evenings. I also changed the type of shoes I would wear. Low to no heals, no scraps across the tops to aggravate the swelling when it happened, nothing that would hold my feet hostage if they were to swell. I also noticed that the swelling was worse and more noticeable later on in the day. On the weekends I wore sneakers and I made sure that the shoe strings were not tied too tight.
Now, for the past two years, it has dramatically improved. I can wear hells again. The pain still comes back from time to time (once very month or every other month), but is no where near the magnitude that it was when I was really suffering.
Hope this helps!