I injured my lower back a while a go, maybe 6 or 8 months ago doing deads and lost form on a heavy lift

Hurt like holy hell the next few days, but healed up and has been fine up until the other day. Seems as if I pulled my back again lifting the 105lb DBs off the floor like a dumbass I guess I was a little to hasty at lifting them. Proper lift and all bend down and lift with both hands between legs, but I seem to put extra force on my lower back for some reason.
Two questions:
Is this common and will heal again just fine, I shouldn't worry? Or could this injury be serious? I can still lift plenty of weight, it's just very painful the next few days.
What can I do I keep this from happening again? Maybe I simply need to pay more attention to form
Hell if I know... I would like some thoughts, ideas, experiences with lower back injuries.