Did the doctor do an ultrasound or any other kind of test when you showed her the lump? There are lots of kinds of bumps and lumps that people can have for years that are not dangerous at all, and since you've had this for a long time, the chances are it's OK. However, because this one is growing, I'd suggest going back to the doctor. A needle biopsy can be done in the office to check to make sure there is nothing wrong.