Angella, it's up to you whether you want to remove it. Also probably up to your insurance company, and your ability to pay should insurance not cover it. Did the ultrasound reveal that this is a cyst? If so, you could have it drained. If not, how does the doctor know it's a benign lump, unless you've had a biopsy?

Once you determine that this is indeed a benign lump (and don't let the doctor tell you "you're too young for breast cancer"), if it would give you greater peace of mind to have it removed, then you should definitely consider it. There's no evidence that leaving it where it is will increase your risk for breast cancer; but it might continue to grow and eventually become painful, which would be reason to take care of it sooner ratehr than later. Good luck - PJH