Chronic lower back pain? how to live/workout around it?

Few years back I was moving some furniture and strained my back(at least that's what my doc told me) I was with pretty bad back pains for months. Ever since then I had recurring lower back pains, on and off. I will admit that for a couple years after that I spent alot of time sitting around during school/work and not doing much exercise.
Went again to the doctor and she told me I have chronic lower back pain, but I don't know...she didn't do too much checking...

Usually there is not pain from just doing normal tasks, but if i sit for a while my back become stiff.
The pain comes when I try to do a hamstring stretch(try to touch my toes) or try to bend over with straight legs, I get shooting pain my lower back and kind of on the sides of pelvis/ tailbone...just while I stretch
However, sometimes it gets worse for couple days and I would have difficulty sitting down or walking...it would be painful

I started going to the gym in past 6months, and my back has been better and worse. I was able to do most workouts fine, and started doing squats/deadlifts with light weight in past month (I tried to do as much of a proper form as I learned from videos/reading)
I was doing squats couple days ago and my pain got pretty bad a day after, I couldn't sleep, and only found relief while laying on back or stomach with legs flat.
Now its better but something concerns me, while sitting down I get sudden shooting pains going down my left leg and groin area...I've been trying to self diagnose it but not sure, I think I got a nerve pinched or maybe dislodged disc?

Anyway, any1 has any idea what exactly it is and how can i possible cure it? is it curable?
Biggest problem I got is that I cant do my leg workout routines when it gets bad, nor I can do bent over rows...I end up doing one handed once with knee on the bench, but my back was still hurting a little.