You may want to try supplementing with CoQ10.
Google on CoQ10 +statins or statin myopathy treatment
I've been using CoQ10 for several months now and when I call on the legs for some extra in a sprint to when climbing, they answer the call and respond. This was an effect I experienced after a couple of weeks.
I started the Co Q-10 a year ago. At 70. Had problems adjusting to cold weather in the fall. Was starting with memory problems.
If any of you had industrial exposure to TCE or PCE you can have memory problems that mimic Parkinsons Disease. After I stated the Co Q-10 I spoke with some other bikers who are in their 60's and were seeing ride quality dropping with age. When they tried the Co Q-10 they noticed a good improvement in their rides.