Need a doctor or anyone help me make sense of this. INFO:Im a women(mom),close to 27, average weight and size?

I have been having problems with my back for a year now and the doctors cant make sense of it. I work in banquets(parties like weddings) as a server for about three years. At that job you lift trays that can weigh anywhere from 30-60 lbs. over and over (reason why I stay it is the best that I have made so far) at the end of every shift my lower back hurts pretty bad and I feel it more when I cough or sneeze. and nothing takes the pain away even if I took 3 extra strength pain killers like ibuprofen, Tylenol, ect. Then I had an incident where I was shoved in my back and my body/back did a whiplash type of move but it was the most painfullest experience that I ever felt, ever step I took, every twist or any move would hurt crucialy. It took awhile to heal when it did it didnt heal all the way, so it seems. Im still having the normal low backpain when I lift at the end of my shift, but also from the injury I have pain on the side of the injured part low right side of my back that can go into my hip and down my leg but they mostly hurt at diffrent times not all at once( rotates daily). My doctor doesnt seem to be understanding and thought it was a damaged nerve. Got an MRI. No nerve damage but the nurse on the phone told me its a bulding. I go back to see the doctor and all he talks about that theres no nerve damage puts me therapy, and gave me 120 naproxen, which are not helping me at all. Im just trying to make sense of this there is pain and allot of it and my doctor says there shouldnt be pain. On top of that pain I have bursitis in my right sholder and endometreosis which hurts greatly. I dont know what to do Im in pain and dontunderstand why or what is happening?