How to get rid of potential clogged milk ducts?

Kyndall

I don’t breastfeed but I pump frequently to give my daughter breast milk. Since my milk came in there’s a hard lump in my left breast and that breast barely makes any milk while my other breast can make almost 2 and a half to 3 ounces on its own. I looked up that massaging the area and hot water can help, doing that seems to help a little bit but the area is still very hard and I’m barely getting any milk out of it? Any advice?