Yep, it's called the 'milk line' and breast tissue can develop there during puberty (and sometimes nipples and such, too). During major hormonal shifts, like in pregnancy, you can get similar tingling/discomfort/etc there as you would in your breasts. It's really neat! I learned about it in my lactation courses and was completely fascinated. I'm weird like that
ETA: Here's a bit of info about it:
http://en.wikipedia.org/wiki/Milk_line

ETA: Here's a bit of info about it:
http://en.wikipedia.org/wiki/Milk_line