Are there any major side effects from statins?

Yes: The most common side effects from statins include 1) myalgia and increased CPK from skeletal muscle and 2) elevated liver function tests reflecting liver inflammation. A vast majority of these side effects are benign. There have been instances of severe skeletal muscle damage or severe liver damage but these episodes are very unusual.

Diabetes: There are also new warnings about the possibility of statins causing diabetes. Often however, the benefit of statins, which is well proven, far outweighs this risk.