How to fix "low back" pain after gym?

I have been in excruciating pain in the lower back since April. I mean that I have literally been disabled. Doctors told me that there was nothing wrong that could be fixed...."Learn to live with it," "We all get aches & pains at your age," blah, blah, blah! Only 800 mg of NSAIDS and muscle relaxants would help (and not entirely). I tried chiropractic. He pushed so hard that he actually cracked the cartilage between my ribs...and then I was in even more pain for weeks! I tried physical therapy. She showed me a few exercises that just made me more sore and told me to "listen to your body...if it hurts, don't do it." Yesterday, I watched your video, did the floor exercise, and IMMEDIATELY noticed a difference after two sets of 10 reps each. This was the first morning I was able to get out of bed and stand up straight without being in excruciating pain. Today, I'm continuing the floor exercise and beginning the second standing exercise against the wall.

I have had back problems for 20 years including 3 horrible car wrecks and while I was in my early 20’s I spent most of my weekends for 5 years in the ring as a pro wrestler trying to work around my injuries. Sadly, around 2007 I gave up my dream to to crippling pain and depression. I became a recluse and wound up on a cane. A little over a year ago I began battling back out of the darkness and into being healthy. 

To fix this quickly, you will want to lay down on the ground with your affected side on top. If your right lower back was bothering you then you would want to lie on your left hip. From here, take your thumb and place it on the area most sore. You should feel that this is going to happen just to the outside of the bony prominence of your pelvis. From here, push to hold back the trigger point and start flossing your leg down and in front of you and then back and up. Your hip should be extended and then lifted into abduction towards the ceiling (being sure to point the toes down to keep the glute medius in focus). Do this about 10 times until you feel the tension in the muscle release. Now, you can burn out the spasm in the trigger point by getting into the fully contracted position of the glute medius muscle and holding as long as you can. Generally, because this muscle is often very weak, this may not be any longer than 30 seconds to a minute. Once you cannot hold it any more you will stand up and you should notice an immediate relief of the pain on that side. This is the quick but not permanent fix for this problem. Since the underlying cause is weakness in the gluteus medius muscle you will want to back this up with some exercises for your low back that you can do a few times a week. I show you three options for this. The first is the hip bump against the wall. The second is called the sack swinger, and can be done with a dog leash if you don’t have a formal dip belt. The last is actually doing the same movement that you did for the treatment, but this time as a strengthening exercise for your low back. Whatever you do, just be sure you are consistent. You will also see that as you relieve the tension in this muscle that your squat performance improves as well. Your depth should be increased and any low back pain that you felt by doing the exercise should be gone since you will now be able to do them with equal force through each leg.

I was once hurt my lower back and caused my back and right leg pain, cant bend and feel difficult to walk. Since it is 90% recovered till now, my lower back's muscle and hip's muscle starting feel tight after sitting too long or driving (sometimes a little bit pain). Then I visited a physician and he told me, even though he can fix my back side (I need to change some of my bad living style after treatment) but he said, I cannot do jogging or any waist related exercise(exercise that use strength to pull something toward to our body) as it will hurt my lower back