xmfd
Winger
Without being pedantic, Deadlifts shouldn't hurt your back so your technique is obviously not quite right.
I do 5x5 after two sets of 8-10 warming up.
Think I was focusing too much on keeping my core tight and actually rounding/over flexing my lumbar spine from squeezing my abs too much. Now concentrating on keeping a totally neutral spine and no issues. Class.