What is this itchy painful rash on my shoulder ? have history of shingles.

Recurrent shingles: According to the 2008 edition of "harrison's principles of internal medicine, " recurrent shingles results from deficits in cell-mediated immunity, the same problem that people with aids have, and, sometimes, inability to make sufficient antibodies. The two processes are usually linked because antibody production depends on communication between t-cells and b-cells of the immune system. See doc.