EM@3AM: Hyper- and HypoCa

A 59-year-old male with history of CML presents to the emergency department with left sided flank pain. He was sitting in a chair 4 hours ago when the pain suddenly started. The pain has been constant since onset. He appears uncomfortable, with mild tenderness in the LLQ. Testicular exam is normal. What is your presumed diagnosis, and what is the most likely contributor?