Shouldering the Burden

Question:    A 67 year old male undergoes an uncomplicated right partial glossectomy and supra-omohyoid right neck dissection for a T2 floor of mouth squamous cell carcinoma.  Two weeks postoperatively he complains of persistent right shoulder pain.  His incision is well healed and there is no evidence of seroma, hematoma, or infection.  What is your next step in management?  [Answer will be posted with next week's new question]

Answer to last week's question, Can the Past Predict the Future? (November 23, 2015): 

The patient likely developed a traumatic arteriovenous malformation.