Lumpectomy - what can i expect?

Hi, I had my lumpectomy last Monday, so its been a week. The problem I'm having is the pain from where they took the lymph nodes out and right under my arm is very painful still and I keep getting these shooting, almost like a bolt of electricity up my arm, has anyone ever had this. I just don't know if this is normal or should I be concerned about it? Thanks for any help you could give me.