I had horrible pain in my left side for about 15 years. I also had major colon problems. I never knew the two were related! Like your pain it was constant. When I cleaned my colon, the pain went away and it has not returned. This is after a kazillion tests and x-rays and ultasaounds and a trip to the ER and specialists.
I agree with Lapis, and would recommend you read FIt for Life by Harvey diamond. He talks about food combining very sensibly and clearly.
For me, I did the Dr. Schulze intestinal celanse. That's what took the pain away (and did load of other stuff to help me too!) And this despite the fact that my eating habits are not the greatest.
Now I'm thinking I might muster up some courage and do a clonic too.