Soft, painless swelling in both nipples during the teenage years is usually pubertal gynecomastia, a common and temporary hormone shift as your body goes through puberty. No pain, redness, discharge or hard lump are all reassuring signs. It often settles on its own within a year or two as hormone levels balance out.
Next Steps
Keep watching it over the next several months while your weight gain continues steadily. If it keeps growing, turns hard, lopsided, painful, or starts discharging, please consult a physician or endocrinologist, who may suggest a hormone panel.
Health Tips
Rapid weight swings can sometimes add to the fullness too, so aim for steady weight gain rather than sudden changes.