I ran a Stop sign while driving. Will I have to go to traffic school?

That depends on whether or not you were caught by a police officer, and if you are a repeat offender. Running a stop sign is a moving violation, which can result in a ticket (a fine), and or points against your license. Typically, if this was your first violation, you might get off with a citation or a warning. At the most you will be fined, but the key here is, if you have points on your license. If you have too many traffic violations within the same time span, then yes, you would be required to go back to your local DMV to retake a course. 

Did you get caught, dumbass?  Therein lies your answer. 

If a citation was issued, going to traffic school might be an option to avoid points and or a fine. In most states driving school is considered an interdiction and not a punishment. Having to take the practical part of the driving test is more likely.

Maybe.  Were you stopped and ticketed by the police?  Do you have any other points/moving violations on your record?  Is traffic school even an option in your undisclosed location?