What Causes Optic Neuritis With Lesions In Brain?

I have been having different health problems for over a year now and doctors cant seem to find out what is wrong. I had optic neuritous and took an mri and had some lesions on my brain but not enough to make a dignosis of MS. Also I have joint pains and expecially in my elbow lately where I cant bend it as much or it hurts. I also have a smething wrong with my blood because I get cold easily and my fingers turn white then blue or purple and cold to touch.