I have been told I have Shingles, but it's strange that ever since I have been on pain meds. I have developed this rash. I have had RSD for ten yrs. The last three almost four I have been on constant pain meds. such as viccadone, ultram, methadone, and morfene. I have been trying and trying to research which types of meds. may cause this type of rash. I have not had much luck.