The goal of this observational study is to learn about the analgesia nociceptive index (ANI) is associated with pain sensitivity in patients between the ages of 9-17 who are experiencing chronic pain. The main question it aims to answer is:
\- Does the ANI score correlate with the change in the pain sensitivity in patients aged 9-17 undergoing an interventional block.
Patients already receiving an interventional block as part of their regular medical care for chronic pain will have their level of pain recorded during clinic appointments