ENTERTAINMENT
August 1, 1991 | MIKE BOEHM
Dr. Howard Fishbein, amateur rock musician, says he used to stand backstage at Irvine Meadows Amphitheatre and dream: "Let me come on stage one time, for one song." Fishbein was used to watching and wishing from close quarters--he has been Irvine Meadows' on-call physician, attending to performers' medical needs, since the venue opened 10 years ago. Last Sept. 2, the fantasy came true. Fishbein and his band, Dr.