Drugs, and interactions, can effect people differently. I checked ONE drug interaction site that said something like "No interactions found for [those two drugs]", but I think it would be prudent to check a few other sites, ask your pharmacist/doctor... stuff like that.

I don't know if they would cancel each other out or if the amphetamine would act as a potentiator for the morphine (which could potentially be dangerous, depending on variables) which is why I'd run it by a professional.

At the risk of once again .... Have you had your adrenal hormones checked? Intractable pain and long-term opioid use can deplete/suppress them, and that can cause fatigue (among other things). I know my energy levels are higher since supplementing my adrenals (which tested at or below minimums).
http://www.practicalpainmanagement.c...tractable-pain

Doc