welcome emma, sorry to hear you're having a rough time.
what i can tell you is that since i started researching ms nutrition, what i've learned is applicable to many other conditions.
ms patients tend to be lower in magnesium, and many of your problems suggest magnesium involvement to me, including restless legs, shortness of breath, the odd feeling in your throat, twitching, headaches, fatigue and irritability.
do you eat lots of magnesium-rich foods? swiss chard and spinach are two excellent sources.
a little reading: http://whfoods.org/genpage.php?tname=nutrient&dbid=75