I'd also suggest seeing a doctor to rule out what Titchou mentioned. Either one will be treated with some medication your doctor will give you.
Temporary, you can use some sore throat drops (I suggest sugar free if you will be eating them OFTEN- I know a few people who used the ones with sugar nonstop for a bad sore throat and got a tongue yeast infection!) and pick up some throat spray. The sprays will help nurab your throat some. These WILL NOT solve the problem if it's an infection though, so you definitely need to see a doctor to make sure that isn't the case.
Is the back of your throat red? Try to look in a mirror with your tongue sticking out. See if you have any of the strep throat symptoms. I used to get tonsil stones that were very painful - and unfortunately they seemed to be caused by my allergies and were on and off for a year until I moved. With these, you would see a white lump to the side of your throat around the tonsil area. Hopefully a doctor would be able to help you out with this too.