This is the manga Beck...
Its a story about rock music,the best manga i have read.
"Tanaka Yukio, whose nickname was Koyuki, was an ordinary student who didn't have special interests or specialties. One day, because he helped a strange dog named BECK, he got to know the dog's master.
He used to think of a pop star, Kuniyoshi Chiemi, who came from Okinawa as the best artist ever. However, the shocking meeting with a charismatic band group, Dying Breed, something in his life began to change."