In fact this is a hugely complex subject and it's not full understood yet, but in brief if stimulates many of the same emotional meta responses as speech/communication. There is also good reasoning based on mathematics and the physical way the ear works that explains why certain ratios of frequencies are deemed pleasant or unpleasant.
BTW, one interesting phenomena is that people who have learned to hear with a cochlea implant apparently find that music doesn't really work for them.
Birds like music..
birds dance and make music to communicate, bees dance to communicate
Are there any other animals that like music or is it just us?
