Girls, I've had this happen where one breast feels like it's swollen, …

Girls, I've had this happen where one breast feels like it's swollen, at first I thought it was lumps, but it doesn't seem that way, it's swelling and hurting, like it's filled with milk, a baby is sucking, it becomes normal and then fills up again quickly. The other breast is normal, as usual, when she sucks - it empties - gradually fills up. The second one is really too much milk, like... I don't know what to do. Initially, this breast only secreted colostrum and milk went better, maybe I think I held it more often and it became more milk?