Back injury/tightness

I did a little reading around on back injuries and chiropraticors but still had some questions. Doc Sust seems to be the authority but I see he has not been on in 3+ months.

My question is mainly the best and most effective ways to stretch entire back (upper and lower). I've been doing high rep deads, squats, and cleans-to-press. Dead and Squats really are not my problem. The over head pressing part of the clean/press I feel like I am tweeking my lower back.

That in turn is making my back feel tighter and now my hip flewors which I feel like are hindering my squating a bit.

Suggestions? Anyone else? Don't want to wear a lifting belt but wondering if other prefer to with hang clean/presses?

Any input is good input...thanks!