Your starting position on your deadlift is way off, you need to have your shoulders out over the bar, and the bar close to your shins. You also need to get on your heels and not on your toes, that is definitely contributing to the lower back pain as your giving away a ton of leverage to the bar. Take your time at the start of the deadlift, before you begin pulling. Bigger arch, chest spread more, turn your belt line down to the floor, weight on heels, and start the bar 1 inch away from your shins, when your shins are at a perpendicular angle to the floor.
Cant tell anything about your squat without a video, but if youre on your toes during your deads your likely doing that on your squat as well.