Cognitive Behavioral Factors and Central Sensitization in Chronic Shoulder Pain

Inclusion Criteria: (1)chronic unilateral shoulder pain (Chronic pain will be defined as pain lasting for 3 or more months. Also, pain intensity will be at least 3 on a 0-10 numerical pain rating scale on most days of the last 3 months). Exclusion Criteria: 1. recent shoulder dislocation (1 year prior) and/or systemic diseases such as rheumatoid arthritis, fibromyalgia and/or polymyalgia rheumatic 2. shoulder pain considered to be originated from the cervical region, and other traumas, 3. neurological dysfunction (ie, multiple sclerosis or stroke), osteoporosis, haemophilia and/or cancer 4. shoulder surgery 5. participants with shoulder pain after post fracture 6. Being pregnant or given birth in the preceding year 7. Overconsumption of alcohol or any other recreational drug2 8. Cognitive impairment 9. inability to provide informed consent and/or complete written questionnaires If participants use medication with a known influence on the central nervous system (eg, anti-epileptic and antidepressant, analgesics, and/or NSAID's), it should be stable in medication intake for at least 1 month prior to his/her participation to be included in this study (Kuppers et al. 2017). Patients are required to continue usual care at least 6 weeks prior to study participation to obtain a steady state.