Hi!
A very common cause of "restless leg syndrome" is Aspartame toxicity. It could be that the reason you got this in conjunction with the cold medications is that many over the counter cold medications contain Aspartame (or more dangerous "Aculefame K" or "potassium K"). The brand names for Aspartame include Nutrasweet, and Equal.
You can do a google search on: aspartame "restless leg syndrome"
and you will come up with a lot of informative reading material. http://www.holisticmed.com/aspartame/ also has some links on it. As does Dorway.com (though that site is a little angry and over zealous for my taste). Aspartame poisoning is a very real thing. I used to go to the E.R with chest pains from drinking diet coke before learning about this. And for many people the amount innocently hiding in toothpaste is enough to cause symptoms.