Scared

Hi guys new to this just hoping I can get a hand hold and surly relate to someone so just before my monthly cycle this month I was having a prod about and on my right breast I felt some dense tissue it took me a while to notice so I kept feeling and prodding on it over Christmas. To me it feels denser than other breast tissue but now I have made it feel like a lump. The lump is behind my nipple but only have it on the right side can anyone else relate? Does anyone also have dense tissue behind nipple. Thanks