mumsie - my own experience was that I took simvastatin for 2 years with no problems, then started to develop several muscle pains in my arms. Back to doc, reduced dose on artorvastain - no difference. Came off them in February and very slowly the pain subsided - very little now but I am having physio to improve the muscle strength (I didn't use them because it hurt!). My cholesterol has gone back up, so I am trying to get that down with diet......
It's worth mentioning that there are new NICE guidelines for management of coronary heart disease and statin prescribing, and if someone's overall risk is below a certain percentage level, statins are not now recommended as an automatic prescription. Mine's estimated at 14% (age, weight, family history etc) and in view of my reaction, the GP has taken me off the statin and is monitoring me regularly as an alternative - next review in November.