what were you doing right before it happened. How many miles do you have. Did it come on when you started the truck or just while driving?
Just asking why it came on without letting us know what you were doing or had done previous does not help.
the SES light is the computer telling you something has happened. But it has so many codes that it could be anything from an o2 sensor that is running lean to long and set the SES off. To that your spark timing is way off....to a knock sensor failing...it can be anything.
If you have a diagnostic scanner i would suggest scanning it getting the code. If you do not take it to someone that does. I know that some dealers will scan your system for free and clear your codes for free if there is not a true problem.