Hi danijav,
This is a bit of an older post, but I'm wondering if you have found the cause of your weight loss and pain? I also have been having pain on my lower right side, that even tops my joint pain from RA, it has been so painful. My gp also had the u/s done plus a ct scan done with contrast and nothing could be found. I've also lost 10lbs and I'm now down to 96lbs. My blood pressure is either too high or too low, it keeps going up and down, and the nurse commented on how pale I looked. I know that it is frustrating to hurt and nothing can really be found to be wrong! At this point I'm starting to feel like a hypochondriach! But I know I'm not imagining it, and I came across your post of weight loss, pain etc and I thought maybe you had found an answer.
Someone mentioned gluten? The day I drank the two bottles of contrast it stated on the bottles that they contained gluten. By the time I reached the hospital my stomach was terribly upset and I was visiting the bathroom, they had to wait on me. I spent the rest of my morning and early afternoon the same way. I'm not sure if it was just the contrast shakes themselves, since I have GP and the lab tech said most of it was still in my stomach, or if the gluten that it contained made me sick.
I hope the cymbalta works for you.