Hi, I am a 59 year old women who has been having sporadic happenings of light-headedness, tingling in the arms and even scalp. I can be fine and then all of a sudden this will happen for just a couple of minutes and then I will be fine again. Along with it I sometimes feel like I may be a bit sick or have diarrhea, but neither of those things have happened. There is no pain in the chest. What could I be experiencing?