What Causes A Painful Lump On The Breast After A Breast Lift Treatment?

i had a breast lift a year and a half ago and recently discovered a painful lump in my breast. I have been told by my primary dr that it is in the area of the incision and is not a concern. when I discovered it it was on the underneath side of my breast and has now moved to under the areola, it comes and goes with swelling and redness as well as gets larger then smaller. I have contacted the plastic surgeon as a breast center does not want to deal with it because of the lift and the the surgeon doesn t seem to concerned. what are my options?