Lumpy left breast

I am a 26 year old mom. I’ve breastfed both my children. I have had mastitis and clogged ducts in my left breast several times over the 5 years that I have breastfed. My left breast feels very lumpy/bumpy. They feel round from what I can tell. They don’t hurt but real concerned by it. I have had my breast examined and the doctor didn’t seem to concerned at the time. But still nervous. Looking for some advice. Thanks!