4 weeks out why does my lower back hurt

Probably because as you are losing weight you are perhaps starting to stand a little taller (not weighed down so much), possibly you are a little more active now? And as you lose the weight, things will shift, just like during the later part of a pregnancy your hips will spread to accomodate delivery so will you find that things will shift as you lose weight. Maybe if you were large in the stomach area you might have been kinda "resting" on yourself when you were sitting and now that you are losing your muscles are being used to hold yourself upright when sitting? Maybe? At least that is some of the explanations that I have read in past posts from others.

How much have you lost so far?

28lbs