If you dream of playing a musical instrument, it can mean you desire music and the aesthetic aspects of life. Perhaps your life has been all work and no play. Maybe your subconscious mind yearns for beauty, pleasant stimulations and the extra “desserts” available in life. Playing a musical instrument to make pleasing sounds can also imply your need to be heard above the humdrum din of daily life.
If you a already a musician, then dreaming of playing music does not hold specific meanings to you. This dream is likely played in your dream because of the continuation of what you do during your day.
If you had been anxious about playing music for an important function, then your stress may have triggered this dream. The prevalent thought that plagued your mind during your day, has been replayed in your dream.