Blood tests for bone mets

Just wondering whether it was likely/ possible to have bone Mets with a normal alkaline phosphatase result .I am waiting for a bone scan for spine and rib pain which is getting progressively worse over past month but was just a niggle for the preceding 9 months .Need codeine every night now! Only blood test slightly out of range was serum calcium of 2.64 .Is this a n indication that I am probably worrying about nothing?
My history is IDC 2004 ER+ HER- 4/14 nodes .
Thank you in advance for any advice. I feel so alone worrying