I get a pulling, burning sensation sometimes. I thought maybe it's a nerve thing, cause it tends to happen after dd has been doing horrible stretchy things with my nipple. The burning sensation (kinda like static electricity) goes right back to under my arm. It doesn't last long and happens every few days. The burning sensation I had when I had thrush was a hot, burning sensation that felt more like cut glass and it was a constant pain that never went away. The fact that it happens to you when you move might indicate it's a nerve thing. Is your baby a gentle nurser? Do you think it may be caused by bad latching?