I found a lump on my lower back more to the side between my rib it hurts me at times specially when i take deep breaths. is nickel size. should i worr?

See a doctor: You should have this mass examined by a physician. Although more than likely it is a benign mass, this can only be ascertained during a full physical examination.

Hard to say: Most commonly these can be lipomas or cysts but it needs to be examined by a physician to help figure out whether this may be something more serious.

Get it checked: Odds are this is a benign fatty growth but i would have your doctor check it out.

Get examined: Any problem with breathing should be evaluated. History, especially of trauma, is important. Your medical conditions need to be noted and diagnostic imaging may be required.