Have you had any allergy tests done? The symptoms you wrote about could be allergy related or else I would tend to think it IS anxiety/stress. You've already been tested for everything else from the sounds of it! I know first hand how anxiety can create symptoms of diseases that do not exist ( I too once had a world of symptoms that did not match anything in medical history). If you take a look at your symptoms separately you can see that each one is relatively minor and none of them appear to be indicative of any major disease. It's the combination of them all that is making you worry, and stress CAN cause chronic pain!

I would suggest asking for anti-anxiety medication or amitriptyline to see if that helps.