Cheryl,

Even though a breast lump can be a number of things (and not always cancer, by the way), yes -- it's best to be examined by a doctor. Please see:

Breast Lump FAQs

http://www.healthcentral.com/breast-cancer/check-a-symptom-35592-5.html

If you need more information, just let me know.

Best,

Maria

Since it is under your breast and on top of your rib, I would question if you have a rib fracture as my recent one felt a lot like that.  But in any case, breast tissue can extend down that far, and as far up as your shoulder - so it really could be anything.  Your best bet is to see your doctor and have some xrays, ultrasounds or even a PET CT scan done.  Those tests there can produce some very accurate results.  I hope that helps some, if not please feel free to ask more questions!

Angi

Hi Cheryl: While in general, breast tumors don't hurt; and they're in the breast, not beneath it; it's always a good idea to get any lumps checked. It'll help your peace of mind. Go ahead and DO make an appointment, but don't panic... OK? - PJH