Mastitis?

Lately I have been noticing one breast that does not empty all the way. Whether it’s pumping or bf at the end of a session I can still feel hard full milk ducts in my breast. It doesn’t hurt at all so I ruled out mastitis but maybe I’m wrong?

My right breast has a faster let down and will empty without a problem. With pumping, the right breast will finish however I have to continue with the left for another 5-10 mins for the left to try and catch up as I have noticed either less holes and/or just a slower let down.

Any advice from those who are bf/pumping or have experienced this?