I've been fighting this for a bit over a month now. Went to the Dr last week, said to use when need, and anti-inflammatories (advil, aleve, aspirin) and basically wait it out. Some days are better than others. She said I can continue my current exercise routine, as long as what I'm doing doesn't hurt or aggravate my back. To me, deadlifts feel good, bc they get a good stretch in the muscle. Mine was feeling pretty good til the other day, when I tweaked it again. I was sitting on the bed and bent over to pick up a sock off the floor and OW!!!!! Stupid sock!

Mine bugs me when I sit for long periods, so I find moving alot helps it from kinking back up. And lots of stretching. What feels best is to sit indian style and lean over to the left across my knee as far as I can to stretch my low right back (the part I hurt)
I didn't hurt mine by exercising, I hurt it by stupidity. I had finished a workout and was tired and lazy. I keep my wts lined up on the floor by the wall, and had pushed my bench in front of them so it was out of the way. Instead of moving the bench, I reached over it and down to put down a 30# dumbbell with my right arm and yanked the right side of my back. Yes, I know better, yes I am an idiot. So now I am paying for it. It is feeling better again now since the sock tweak a couple days ago. But I'm sure it will be sometime before it is 100% Dr said the back strain can take months to completely go away, but the best is to keep it moving w/in the comfortable limits. I can say for me that is true. Being inactive makes it hurt worse and kink up bad.
Try getting a microwaveable heating pad, or put some instant rice in an old, clean tube sock until it is mostly full, tie the end in a knot and put in the microwave for 1 to 1 1/2 minutes. Ahhhhhhh.......
Hope you are feeling better soon.
Nan