effects of Metoprolol

I have a two part question: My father has recently had a kidney removed due to renal cancer. He is doing well, however, he is cold all of the time. He has episodes of shaking uncontrolably despite the fact that the temperature is well above normal. Doctors tell him that it might be due to his heart medications. He takes metoprolol 100mgx 2, Nitron, and cipro.  Are any of these pills responsible for this coldness. He also has been experiencing vivid nightmares and calling out in his sleep.
The second thing is could you tell me the difference in the symptoms for atrial fib. and pvc?  Thanks for your help and this wonderful service!

Norm

[CCF CARDIO MD - DLB]

Atrial fibrillation and PVCs can both cause similar symptoms or no symptoms. You cannot tell the difference yourself.

Metoprolol can cause vivid nightmares as a side effect. It can decrease blood flow to the skin in people with circulatory problems, but should not lead to shaking chills.

[Norm]

I forgot to mention that my father also takes Lipitor to reduce cholestorol.

[CCF CARDIO MD - DLB]

These do not sound like side effects from lipitor.