The purpose of the study is to discover at least two distinct Musculoskeletal pain subtypes. These types are caused by different brain-and-immune system signals that affect how the body feels pain, and they are also shaped by a person's biology, psychology, and social environment.

Aim 1. We want to sort adolescents and young adults with long lasting muscle and bone pain into two different groups. To do this, we will look at participants' childhood medical histories, past treatments, when their pain started, the sex they were assigned at birth, what their pain feels like now, tests of how their body senses pain, and immune system markers found in their blood. We think we will find at least two different types of chronic pain groups, plus one group of patients who had a higher risk for pain (because of a rheumatic disease or past surgery) but never developed long term pain.

Aim 2. We want to find out if certain patterns of inflammation in the body change how nerve cells react to pain.

Aim 3: We want to understand how different biological, psychological, and social factors are connected to the chronic pain groups we identified. We think we will find certain mental, behavioral, and social risks-as well as protective factors-that help explain why some people develop long-lasting pain and others do not. We expect these factors to play different roles in each pain group, including the group that does not develop chronic pain.

Inclusion Criteria:

• Diagnosis of rheumatic/autoimmune disease/pain condition or surgery prior to age 18; Current age 14 to 26 years; Participant (and parent/legal guardian of participants < 18 yo) can read and write in English; At least 1 year from diagnosis of pain or rheumatic disease; For individuals with MSK surgical history, at least 1 year after initial surgical intervention; For individuals with rheumatic disease, their disease must be considered inactive

Exclusion Criteria:

• They have active disease, or Other major medical comorbidities have developed after surgery following MSK surgical intervention.

The participants in this study will come from several groups at Cincinnati Children's Hospital. These include teens and young adults with long-lasting widespread pain, patients already taking part in chronic muscle and bone pain studies, patients with childhood rheumatic diseases, and patients who have had major muscle or bone surgeries. If we need more participants, we will also recruit from the hospital's rheumatology and pain clinics. We plan to enroll 600 adolescents and young adults, ages 14 to 26, with equal numbers from each of the three study groups.