Statins block the liver's production of LDL, a lipoprotein "bubble". Because fats are insoluble in water, but LDL is, LDL is required to carry fats around the body and deliver them to cells; a sort of fat version of insulin. Although LDL has a stigma attached to it, it carries the so-called essential fatty acids around as well as cholesterol and other fats. Fats are essential to the body's cells - every cell membrane in your body is made from cholesterol (although most cells can make cholesterol themselves) as well as the synapses in your brain.
Therefore, if your LDL is too low then your cells will not function properly. Muscle aches is a textbook symptom that your dose of Statins is too high. Best thing to do is to speak to your doctor who will likely lower your dose.