Subacromial Corticosteroid Injections and tDCS in Rotator Cuff Tendinopathy

Inclusion Criteria: * Shoulder pain for at least 9 months * Trial of conservative treatment prior to inclusion * Positive painful arc sign * At least one positive impingement test (Neer or Hawkin's impingement sign) * Written and oral comprehension of French and/or English Exclusion Criteria specific to rotator cuff tendinopathy and CSI: * Traumatic origin * Diagnosis of a systemic inflammatory joint disease * Complete rotator cuff tear on physical examination or MRI * Diagnosis of acromio-clavicular syndrome * Presence of cervical nerve root pain or symptoms * Other confounding pathologies seen clinically or radiographically * History of previous fracture or surgery at the shoulder * Contraindication to CSI * CSI received in the last three months * Planned or ongoing pregnancy * Receiving worker's compensation or being involved in litigation relating to the shoulder pathology. * Inability to follow protocol instructions Exclusion Criteria specific to tDCS and transcranial magnetic stimulation: * History of epilepsy or convulsions * Brain metallic implants or fragments * Brain lesions or tumors * Use of a pacemaker or ICD * Use of an intravenous medication pump * Severe cardiac disease, or recent cardiac event * Consumption of medications known to lower the seizure threshold * Alcoholism * Severe sleep deprivation * Eczema or skin lesions at the area of electrode application