What Causes Pain In Mid Abdomen?

high im a 43 year old male, have been in good health, I started getting a burning pain in my mid abdomin radiating to my back just below my rib about 6 months ago. The first few times I got the pain I was constipated and it would go away upon using the restroom and usualy a discharge of slimy yellowish fluid would follow. My doctor ordered a colonoscopy and blood work, both came back good, I still get the pain now without constipation or discharge my doctor also gave me dicycomine for when the problem acts up which has no effect. the pain can be sharp when I move the wrong way which feels more internal my job requires me to do heavy lifting which usualy has no effect I have been trying to cut things from my diet and have had no luck, milk, gluten, do you have any recomendations. Thank you