I have a weird pain in my chest/back/shoulder, kind of behind the left breast. It comes and goes - Friday it hurt a lot, then on the weekend I could only feel it if I thought about it, but this evening it started back up again, and hurts worse than ever. It s on the left, but there s no accompanying heart problem (no fluttering, slowing/speeding up, etc.). I carefully checked for a lump in the breast, but there isn t one. I decided when it started hurting again this evening to call my doctor tomorrow, but it hurts so much now, I wonder if I should go to the emergency room.