Could Taking Ace Inhibitor Cause Muscle Pain?

Why/How do ace inhibors cause muscle pain? Is it just pain or is it causing damage too? I am a 66 yr old active woman who has had a quadruple by-pass 12 weeks ago. I have been put on Lisinopril which gave very bad muscle cramping, as the Dr. put it, turning my shoulder and neck muscles to stone . I was switched to Losartan which I can tolerate a little better. I still experience terrible headaches, and chronic shoulder and neck pain every day and am currently living on acetomenphine to get through the day. How does the ace inhibitor cause the muscle pain. And of course, my main concern, is it causing damage as well as pain? I am 5ft and 115 lbs.