I had the same thing with me, standing, sitting, laying, even in the the car I was having problems I told my lupus Derm. she told me to talk to my pcp. My blood pressure was good everytime I went to see him and I was on diovan for blood pressure so I didn't think it would be my blood pressure. Well he put me on norvasc blood pressure med. I also think it can be due to stress that I have. Now I'm on 2 of them, haven't had any problems for 3 months. I would talk to your doc. Good Luck
Advair,Diovan,Actonel,Prednisone on and off Eye Drops,VitaminD.