Inclusion Criteria:

Unilateral shoulder pain within the past 2 weeks Pain during joint movements such as abduction or internal rotation At least one positive result from the following tests: Painful arc, Neer test, or Hawkins test No shoulder injections received in the past 3 months

Willingness to receive injection treatment and undergo follow-up assessments at the following time points:

Immediate (1 week after injection) Short-term (1 month after injection) Mid-term (3 months after injection)

Avoid use of anti-inflammatory painkillers during the study period as much as possible; if intolerable pain occurs, acetaminophen (provided by the researcher) will be used to relieve symptoms

Exclusion Criteria:

Presence of infectious disease, inflammation, rheumatoid arthritis, or fracture History of malignancy Previous shoulder surgery Sensory deficits Tendon rupture of the rotator cuff or biceps tendon Neurological disorders causing hand weakness or affecting shoulder mobility (e.g., stroke, Parkinson's disease, brachial plexus injury, peripheral neuropathy) Cognitive impairment preventing completion of questionnaires Cervical radiculopathy Diagnosed frozen shoulder (adhesive capsulitis) Psychiatric disorders Breastfeeding or pregnant women Received shoulder injection within the past 3 months, including corticosteroids, hyaluronic acid, Platelet-rich plasma, or any prolotherapy solution