A recurring sore throat could also be due to acid reflux. If you do have problems with heartburn, especially on a regular basis, I would either try an over-the-counter acid reducer or go to your regular doctor and get a prescription. In addition, try elevating your head at night if you notice that you wake up with the sore throat or if it is worse in the morning.
The allergies is also a real possibility, as well. If you have problems with those, try those remedies trygi mentioned.
If the problem persists too much longer, you should see either an allergist or a gastroenterologist, depending on the cause (allergies or acid reflux).