In 2014 i was diagnosed with demylination and in 2015 i was diagnosed with chron's and ankylosing spondylitis. is their a link among these?

Autoimmune focus: Ankylosing spondylitis is of genetic origin, and can be confirmed readily. "Demyelination" is nonspecific and not sure if you mean central or peripheral nerve involvement, But the latter two are autoimmune disorders and can on rare occasions cluster together. Other autoimmune contributions should be asked about, and might check B-12 and Vitamin D

Yes and no: Your joint disease is likely to be the "reactive" arthropathy of Crohn's disease, which mimics ankylosing spondylitis. Hopefully you can get treated with one of the new biologicals. "Demyelination" is not a diagnosis, but a process in central and peripheral nerve disease.