That happens to me all the time the solution is I need a push or some deadline. For high school it was a strict (we thought) teacher who brought me from an average of 70% to 95%. For computer programming it was going back to school as an adult and timed in class tests. For music is was paying for lessons at a certain time.

If I don't get motivated from some external push I never get past a certain level. Every single thing I do in my life is like that even laundry. I must be chronic or maybe permanent procrastinator.