Q10 is depleted by statins. Taking Q10 if you are taking any statin drug is well worth it. 30 to 100 mgs is the usual recommended dose. Q10 functions as a vitamin, and is very important in several cellular biomechanical processes.
It has been fairly well researched. If my memory serves me correctly, one of the big pharmacutical companies was in the process of making a statin containing Q10, then decided to pull it, because that would have admitted that statins do have unpleasent side effects.
If you would rather suffer from leg cramps and other aches and pains associated with statin side effects, then don't take "one more pill', otherwise simply add it to your crestor.
Eva, I would be more concerned with the "herbalist" who suggested you stop the Q10.