As at least one other member has suggested an MRI I am going to second that.
I ruptured a disc in my back at a young age which caused problems for years because I thought it wasn't serious and I could train around it.
I ended up with spinal fusion surgery at L5S1 with plates, screws, rods and a titanium cage...pain mostly gone.
Unfortunately, because I waited so long, I ended up with permanent nerve damage which affects my left leg...it gets more noticeable as I get older.
You can get a lot of great advice here. You can get some good opinions, some objective, some not.
You can't get any real medical advice or opinions and it sounds like that's what you need right now.
In the meantime, I'd back off anything that causes the low back pain because you could be making the condition worse.
That's my opinion. I wish you luck and I hope it's nothing serious.