I've only had this happen maybe 2 or 3 times, one of them being tonight. I would be sitting at my computer, hurting in my back and headache, and then all of sudden I would become a little dizzy. Symptoms would be eyes not focusing clear, feel like im spinning, heart rate speeds up a little but. I'm not sure if this is caused by MS or what it is. Only thing that I took was three Tramadol - 2 at one time then another 1 2 hours later (150 mg altogether) for the pain I was having, not sure if it maybe that.