Have you had any recent surgeries? Often that burning, painful feeling can be a result of irratated nerve endings. I know after each of my breast surgeries (there has been about a dozen!) that I've had burning, tingling sensation in odd places (down the back of my arm, my chest, my side) It all depends on if you have had any procedures done that may have upset them.
To answer your ? on needle core biopsy - After the procedure you can expect some bruising, but should be mild. I would say no more of a scar than getting an IV.
Hope that helps!
Angi