Wayne,
I'm happy you are doing well. Your spirit seems to be upbeat. That's all good.
I went through mood swings, cold sweats etc. when my medications were changed ten years ago.
Gary and others are correct, pain management is a key to successful treatment and rehabilitation, but has some down falls. Any medication that has centrally acting agents (CHANGING OR ACTING ON BRAIN RECEPTORS) can cause dependance. I agree with Gary that Vicodin can elicit this. Vicodin is not available in Canada. Matthew Perry, Chandler on Friends was treated for a Vicodin dependance after dental surgery and, at the time was publicly admitting it.
If reducing or changing pain medications is changing your attitude and demeanour you should discuss this with your doctors and enquire about other possibilities.

Cheers,

Mike