Simvastatin and tumour

My husband was prescribed 40mg of this drug 2 years back,for his high cholesterol reading. He is an ex-services and has always been extremely fit, he was tired for almost a year, then he began having headaches to the point he had a brain scan, because he thought he had a tumor. He also has had knee and neck joint problems and now the joints of his fingers are giving him pain He now wakes up each morning feels really ill and feels as though hes being strangled, the sensation lasts sometime for hours and he has to lie down. His doctor said it was blood pressure but he keeps a monitor and his pressure has been normal. His doctor said he should continue to take it, but when you read all the symptoms that people are getting while taking this drug it makes you realize they are all just guinea pigs for a large scale trial of the drug