A lot of younger players get what I call "speeeeeed syndrome" when younger guys get into metal they want to play a million miles per hour and that's all they want to do. I predict you fall into this category. Its not a bad thing at all. Just something you will have to work on. It's just that your speed has developed faster than your technique has. You've skipped over the small things like string muting and the subtle touches of playing clean... Work on the runs at slower speeds keeping the time right... just at a slower bpm... play it as clean as possible then move up. Don't move onto another speed until you can play it clean at the speed you have it at. This exercise works well for all types of music. You will get it, just practice!!! Good Luck