psoriasis fatigue and adenopathy

I have had psoriasis since age 11.I started having Excessive Fatigue in June 2009. I was dx with bilateral intermediate uveitis July 2009 that became chronic. Started Methotrexate for management until Oct. of this year. Thinking Psoriasis as the cause as all labs are neg. including HLA B27. I have had issues now with SI joint dysfunction in the left side with pain referring to right groin and right illiac crest. Very little help from PT. My first question is could all my fatigue and now other issue be from the psoriasis and how should I test if it may be Psoriatic arthritis?
During MRI and CT imaging of my neck in June 2009 there was incidental findings of " unusual nodular irregularity in right thoracic inlet that may represent prominent vascularity or Adenopathy. Somewhat prominent right level 3 lymph node measured at 1.1cm that may be reactive in nature. Unusual nodular lesion within the right thoracic inlet that may represent Adenopathy or possibly vascular anomaly." I understand Psoriasis can react with lymph nodes but due to the ties of Lymphoma, should these findings be followed up with since it has been a year and new symptoms seem to keep popping up with no explanation? Thank you for your anyone.