The symptom of a sore throat is aching in the back of your throat. The throat will also be red and irritated looking, if you can manage to shine a flashlight back there. It can hurt plenty as you lie motionless, but try swallowing and it hurts tenfold. Sore throat may be accompanied by swollen glands in your neck.
Sore throat is a common symptom of a cold. Personally, I'm guaranteed a sore throat if I don't get enough sleep for a few days in a row. Stress and lack of sleep both factor in to a decrease in the effectiveness of your immune system.
There isn't much you can do about a sore throat but wait it out. Drink lots of liquids and get a lot of Vitamin C. If you go to your doctor he might suggest some Zinc lozenges that will subdue the pain, but since it's caused by a virus there is no miracle cure. Even vitamin C may be nothing more than a placebo.
It gets annoying going to the doctor every time you have a sore throat, but it could be strep throat. It usually isn't, but you don't want to try waiting out strep throat -- you might die first.
My rule of thumb is to get a lot of sleep and eat a million grapefruits. If the sore throat isn't subsiding in a day or two, see a doctor.