uveitis cause

I was dx with Bilateral Intermitentant posterior uveitis last July. We have been searching for the cause as it would not go away . Since I have psoriasis we thought that was the cause. My HLA B27 was negative as well as all the other tests we have done. Now I have SI joint issues for the last 4 months. Started gradual pain in left buttox and now alot of pain to top of iliac crest on right side.In my research, I find that these are all tied in  with each other so does this make any sense? Is there any way to tell by this which one is causing which? Or what else we should test for?  Should I bring up this new developement with my dermatologist or Rheumatologist? Should I get MRI of SI joint to check for Psoriatic Arthritis as the possible cause of the Uveitis since I have no other symptoms of it. I will be trying to get off the Methotrexate in Oct. as that will be a year I have been on it for the Uveitis. Please let me know if you have any other ideas.
I also have hypersomnia now with no known cause so I also worry about things like MS.  Thank you for your time with this.  

[Sandy Feldman, MD, MS]

Dear shelly62,

I would recommend that you discuss all of your symptoms with your rheumatologist. He/she should determine whether a further workup should be done.

Dr. Feldman

Sandy T. Feldman, M.D., M.S.
ClearView Eye and Laser Medical Center
San Diego, California