You need to set your back better. Squeeze up hard an avoid dropping your butt. You drop your hips prior to almost every pull and push the bar forward of the midfoot. That is not ideal. Setting up for the deadlift should be uncomfortable. Squeezing your chest up and putting the spine into extension is difficult and feels bad. However, it must be done. I have seen worse, much worse, but I want your back to be flat. Also, instead of looking straight ahead, drop your chin a bit and look at a point on the floor about 15 feet ahead.