Hello dear and thanks for the query
Muscle spasm and cramps, joint and bone pain
are the common side effect of this drug. But as you are using this drug for a week only, I do not think that drugs causing this.
As your mother as multiple problems we have to investigated her for the other causes of the back pain
.This can be due to long sitting or lying down.
Consult you treating doctor before giving next dose of rasalect and find out the other cause of pain if any?