It's a side effect of some of the stronger pain meds. I went through it with Morphine. The deal is that you normally adjust to it and it stops, but the way your taking meds that won't happen, you don't take them long enough at a time. You could make sure it's okay with your doc, and take a low grade antihistamine with it, i.e. benadryl, claritin, allegra, attarax something along these lines. That will probably be the only way to control it, or get on a normal schedule or change meds.