What Do You Suggest For Back Pain When On Therapy?

I hurt my back really bad lifting over 12000 pounds while bending over a crate and lifting items that were 30-75 pounds and lifter over 800 of them then had to lift other things just as heavy twisting and turning and so fourth until i fell onto the ground in so much paid i started to cry and shake.. the work dr said i had a mild lumbar strain which i laughed at because this hurt to bad and he said I could work in 3 days well i couldn't even move for over a week and was in beyond bad pain. I seen many other doctors about this and they say you will be fine and theres nothing we can do. well i had a mri done and they say i have sclerosis along my l4 pars, fatty infiltration of the filum terminale, cyst on my kidney.. long story short i continue to live with terrible pain and ive done therapy and everything you can think of and the pain does not go away.. i no longer can do the same things i use to including sports, i have to lay in bed propped up cannot lay flat or it hurts way to bad. the doctors will not give me anything for pain. I am at the point im about to say enough and go kill myself because this is absolute bullshit and my parents and fiance want me to go to a pain clinic and i know nothing about them.. help help help