Hi Optimist,
Just to say I have been experiencing pain in the same area, noticeably since Mirena, er, 'installed' in December. On holiday at the moment and the other night OH and I were in tent trying to decide whether or not either of us could feel a lump. Inconclusive but we did have a good laugh. I have an appt when we get home just to be sure.
Also have had burning feeling, sense of someone pinching and twisting my nipple which seemed to start around same time as my acid reflux. I think ladies on here have reported similar.
Hope it's helpful to know you're not alone.