If your doing all of the exercises already mentioned you could try switching up your reps, order of exercises and it could be partly genetics.
I really like to stay away from machines for back except the lat pull down machine.
If you don't like barbell rows then t-bar rows are a good alternative. I feel them more in my lats then barbell rows. To each is own with working out though. You kind of have to just keep switching it up until you find what works best for you.