Complex sentence: Mastelotto started playing the drums at the age of 10, by the time he was 16 he was playing in popular local bands and, while still in high school, commuted several hours to Lake Tahoe for gigs.
Split into simpler sentences: Mastelotto started playing the drums at the age of 10. When he was 16, he was playing in popular local bands and, while still in high school, commuted several hours to Lake Tahoe for gigs.