Clogged duct? Mastitis? Something else?

Sa

My left breast got uncomfortably full a few hours ago because I accidentally fed my daughter twice on the right side. I pumped to get out some extra milk. Since then one part of it has been really hurting. I've felt around the area and I don't feel any lumps or bumps that would be a clogged duct. I figure it can't be the start of mastitis because I would need to have clogged ducts for that... so I'm not sure what is going on. Any ideas?