I had arthroscopic rotator cuff repair 8 months ago, and developed a frozen shoulder 3 months later due to scar tissue formation which most likely formed due to me not being able to take NSAID s due to allergy. I am concerned about a lump now in my arm pit which has come and gone since the surgery but has enlarged in the past 3 months. Could this be my lymph node possibly inflamed or damaged from surgery or just scar tissue/sagging out of tone muscles from surgery. I am 48 years old and weigh 123 lbs.