Robyn,
I agree with Bina that it is best to get it checked out, and see what it is. I had Atrial Flutter after surgery, which was something that they definitely wanted to know about and stop, so I was readmitted to the hospital overnight and put on a drug regimen. There are other palpitations that are not as big of an issue, but you would want your doc or cardiologist to make that determination. I currently still get palps when I lay down flat, but they are of a kind that is less of a concern. I did let my doc know about them, and they asked me to let them know if they worsen or if I develop any other symptoms. Again, I would talk to your doc.
Where did you have your surgery? I am in Fargo, not too far from you, although I had to look up Tolna! Didn't know where that was until I looked it up!