Depressin symptoms and conditions

I am a 55 year old male. I have been on 40mg of Lipitor for 2 years after having a stent put into my heart. About 6 years ago I was on 20mg ov Lescol for a year but I stopped taking it because my knees became very weak and I could not walk up stairs without holding on. I am now experiencing severe lower back pain down into my left buttock, leg muscle and knee weakness, and I also have mild depression or a lack of motivation may be a better term. I am going to stop taking the statins and see if I have any improvement. Several years ago, when I stopped taking Lescol, my knee weakness and pain did not improve. Through research on the internet I discovered that some symptoms do not improve by stopping the medication. My goal now is to ensure it does not get any worse.