Low Back, Big Problem

Hello to all. I have problems with low back, left side. 6 months ago when we did the MRI, the problem was not sow big but I kept training in the gym and now it get worst, i feel the pain even when sneezing,I tried all kinds of exercises and stretches, with no results.I really want to fix my back, because I love to train at the gym,is my hobby, but this problem is stop me for any advanced results. I feel like wasting my time at the gym. I been to few private doctors that they ripping me off. I live in London and if anyone here knows any good doctors, specializing in low back problems,please, let me now about it. Thank you, all the best