\\\\and find would it be them giving me this lethargy and joint trouble. \\\
The above symptoms certainly are the side effects of statins that some people do experience, BUT they are also the symptoms of other medical conditions e.g diabetes, under-active thyroid and depressive illnesses. I suppose the only way of sorting it out, is to have blood tests to exclude the disorders mentioned above OR stop taking the statins and see what happens ton your symptoms.
You will need to discus this with your GP as it may be just a matter of changing to another statin and of course is the trade of between feeling ill and preventing a heart attack or stroke, worth it.