My wife's body began to ache today. is this a symptom of her menstrual cycle?

Not usually: You could ask her if she is due to have a menstrual cycle around this time. She can probably tell you where she is in the cycle based on her past history. Body aches are not a typical sign of menstrual cycles for most women. I

Could be: Many woman do feel achy before and during their menstrual periods. There are also many other reasons that a woman could feel achy, for example: working too hard, not drinking enough fluids, viral illness, etc.