I have a question for you....have you experienced having shortness of breath?
The reason I ask is because I have experienced the jerking of legs, extremities, cramping, GERD, feelings of electrical pulses, and tingling. The only one that isn't a part of what I have is the GERD.

I suffer from chronic iron anemia. My liver doesn't store iron like other people do. My body flushes extra iron out of my system, so I do not have an extra supply if I happen to have something throwing my iron levels to lower. Mine will just continue to lower if I don't get iron infusions and/or blood transfusions. One of the signs of not having iron stores is a feeling of being tired, twitching, tingling and itching of extremities. My iron levels 3 years ago got so low that I had to have 4 blood transfusions and 2 iron infusions over a week while in the hospital. I almost died, so I am an advocate of getting your iron stores checked in addition to your iron levels.

I hope that this will help you to at least have one more thing to check and knock off of your list. It isn't very common. It is unusual to have chronic low iron stores but it is worth checking because you could also have acute iron issues which are quite common.