A 2015 meta-analysis of six small, randomized controlled trials found no reduction in statin-induced muscle pain with 100 to 400 mg/day of supplemental coenzyme Q 10 for one to three months (29)
Genovese, I., Ilari, A., Assaraf, Y
In the absence of evidence from labs or the pharmaceutical industry its hard to say
If you are vegetarian or vegan, look for fortified foods or take a B12 supplement as recommended by a healthcare provider
To gauge improvement, track specific issues you had before, for instance, frequency of mouth sores (which can occur with B deficiencies), or numbness in feet, or level of fatigue on a 10-point scale