What is the difference between self discipline and artistic discipline?

Self discipline is self-control, the ability to resist temptations which will sway you from following your long-term plan. It is related to uses of the Word "discipline" which have to do with making people follow rules.

An artistic discipline is a field of study, like painting or sculpture. It is related to uses of the Word "discipline" which have to do with a course of study or action.

The Word "discipline" derives from the same root as "disciple", a follower. You may want to become a follower in order to pursue a particular goal, but in order to do so you must conform to the rules of such followers.