Breast tissue or lump. What it could be?

Hello doctor my age is 24, regular periods cycle varies from 28-30 days no history of pcos, I feel lumpiness in my right breast on Friday (22/08/2025) since Friday I check it often and it has become painful now pain is ok but whenever i press it's slightly painful. I am also near to my periods, so I'm not sure if it's just hormonal changes or a real lump. And my right breast is slight bigger than left, usually before periods I will have mild breast tenderness but simply I have checked breast on Friday since then frequently am trying to check both breast but some times both feeling same few times only right breast. I also have a soft lump in my left underarm since November that hasn't changed. Doctor said it could be fat pad so l ignored. There are no skin changes, no redness, and no nipple discharge. Are the lumpiness is due to hormonal or simply am feeling breast tissue or what it could be? I am preparing for upsc really since Friday worried about cancer. No family history of cancer .