The musicians of the Boston Symphony are reportedly well pleased with James Levine as their new music director, but the maestro’s predilection for over-long programs and extra rehearsals has some players begging for a break. The BSO agreed to several rules changes in order to secure Levine’s services, among them an agreement that there could be more than the traditional 4 rehearsals for a given program. But that extra time on stage has apparently caused several minor injuries already within the orchestra’s ranks, and others are concerned about nagging arm and shoulder pain, as well as simple fatigue. Levine has reportedly been responsive to the musicians’ concerns, and has retooled a couple of programs as a result.