Well, that's my opinion. I thought you were suggesting that what your teacher had said had caused you distress, leading you to think that maybe you should look at changing some things?
I think your reasoning that you are not hurting yourself by your actions and therefore should not change in any way is poor, as you may well being hurting other people. Understand that your classmate was probably just very stressed by not knowing how to do the work and so resorted to cheating out of desperation! If you had encouraged him, explained a question or two to him, or said you can't help sorry you would have done less harm than by doing what you did.
It seems, as others have said, that you do have sociopathic traits - remember that some of the traits are facultative, not indicative, to having a disorder. It's possible to be non-violent but still inflict harm on yourself and other through your inconsiderate and uncaring ways. As I said, this is not some terrible fate or sentence but something you can work on!
I dare you to experiment with just trying a different approach and apologising to the boy you set-up (being caught cheating will have caused him embarrassment and you were a part of that). Try and it and see how it makes you feel!