I suffer from chronic pain and the doctors have very little answers as to why..?

So I have decided upon doing some of my own research to attempt to change my diet and take the nutritional approach. I do not want to be dependent on drugs that treat my symptoms I want this pain to stop. One obvious solution is to loose weight. I am 5'5 and I weigh 195 lbs. and I am female. The pain is in my left leg and generates from my knee, down my calf, and over the top of my foot. I have had MRI's, nerve conductivity tests, x-rays, ultrasounds, and physical therapy. Problem is that because of my pain it has the created me to take to not being as physically active as I once was. I hurt to stand, I hurt to sit, I hurt to lay down, I hurt to do just about any damn thing. I have very few moments that are actually pain free. I have suffered from depression due to all this pain. I cannot describe other then I just freaking hurt all the time. Even squatting down so I can use the toilet hurts! So anyone with any advice on what activities or items to remove from my diet that I may be able to do that could by chance encourage my weight loss and pain free desires?