 This study will recruit individuals who have had muscle symptoms while using a statin. During the first part of the study, volunteers will be given a statin medication to see if their muscle symptoms return. Those who experience muscle symptoms on this statin rechallenge will be invited to continue in the second part of the trial, in which participants will be randomly assigned to receive either CoQ10 or a placebo sugar pill to take with statin medication. We hypothesize that those who receive CoQ10 will experience an improvement in their muscle symptoms compared to those who receive placebo, and, secondarily, that those who receive CoQ10 will be more likely to continue taking the statin medication. 