Pinched nerve is very probable due to the recent surgery.  However, you also want to consider the fact that the symptoms you are describing point toward cervical issues that could be due to the cancer as well.  You need to have the symptoms checked out completely. 

If your current doctor is a good one, he will jump right on this.  I am hoping he is a neurologist.  If your current doctor isn't a neurologist, then get to one.  If your current doctor is a neurologist and does nothing, don't wait around, find yourself another doctor. 

Good luck.