With weightlifting, you will get out of it everything you put into it. In other words, you will become quite strong and build up a lot of muscle, if you wish to do that, by advancing to higher weights and more demanding exercise routines. As you have known back issues, though, you should look for a good trainer, in your case one with PT interests, training, or background, because it is possible to well and truly screw up the back lifting weights if it's not done correctly.