Sickle cell disease is a painful inherited disorder that affects approximately 100,000 people in the United States, and more than half of these individuals develop chronic or persistent pain that is often severe and disabling. The factors that predict whether an individual with sickle cell disease will develop severe, disabling pain are unclear. The goal of this project is to identify the factors that predict severe pain outcomes in individuals living with sickle cell disease in order to improve pain management strategies and guide future studies of non-opioid therapies for treatment of their pain. Participants who agree to enroll in this study will be asked to participate in a virtual and then an in-person study visit for their full initial study assessment. They will answer survey questions during the virtual visit, and will be asked to complete several types of standard testing to understand how their body handles pain during the in-person visit. After completing the virtual and in-person sessions, participants will receive text or electronic medical record messages with brief survey (will take less than 8 minutes to complete) on their pain experiences every three months until the study is completed (or up to 48 months for people who are enrolled at the beginning of the study).