For me, my horrendous knee pain (I was a runner) left, once I emptied my pantry of all processed foods (not negating anything Pamela has said!). I didn't realize until a few weeks after, that I no longer had pain.
Some months ago I bought some low-carb biscuits to have with cheese. Within weeks the pain was back.
I removed them from our diet, and the inflammation left.
There's a lot of non-food, 'food' out there. It's hard not giving into convenience, but I believe factory foods are at the root of much sickness.