Why do coughs seem to last so long after a cold?

United States
@apples99 (6574)
May 27, 2011 4:44pm CST
I'm getting over a bad head cold, but the cough seems to keep going, I've been taking an over the counter cough medicine but it has little to no effect on my cough And the cough is keeping me awake during bedtime does anyone have a good safe home remedy I could try? and why does a cough last so long after other cold symptoms are gone? COUGH,COUGH!