Hi I'm 19 Years Old Hv Lumps On My Both

Hi I'm 19 years old hv lumps on my both breast one on lower left in left breast found 6-7months earlier and two on right breast 2-3 cm away from nipple..they are soft moveable nt growing in size nt even painful..and also I m thin but have fatty underarm pit...cn u suggest me what it could be