Hi welcome to Health care magic forum. Of course perindopril
has the side effect of muscle twitching, for that only you might be getting this back stiffness
. I advise you to consult your doctor for considering this problem ask for a change of the drug.
I advise you to consult an orthopedic surgeon for diagnosis and treatment. a slight change in the vertibral column can have the effect on the back.
I also advise you some diet recommendations as avoid taking more of potato, other tubers, tomato, egg, chicken, and sea foods as these may tend to increase the pain.
Wishing for a quick and complete relief, and thanks for calling.