Heartburn, Nausea, Back Tension, etc...

I was diagnosed with CD when I was 12 years old, now I'm going to be 18 in a month. Normally when my CD acts up I will go to the bathroom a lot and get stomach cramps in my left side, but this past week I have felt really bad nausea but have not got sick, bad heartburn, mild fever(around 99.4-9), really bad tension feeling around my mid back near my kidneys, some chest pains, and pain in both my right and left side. I went to the emergency room 2 days ago and had blood work done for everything and all of it came back fine. I was hooked up to an ekg machine and my heart was fine. 

Does anyone else get these symptoms when they have CD flare ups or can this be something else?

I can't go until after Monday because of the holiday... If I lay down on my back there is no tension or if I lay back in a chair, but when I sit up I get it bad! Right now I'm sitting up and I don't feel it anymore but I feel sick now so idk what it is

Many with Crohns also develop GERD or Acid reflux. This can make you feel nauseous and cause the heartburn. Do you ever find you feel better once you eat a little, then a little while later (after your stomach empties) it comes back? If so, I would think it would be Gerd. But you could also have gallbladder problems as was suggested above. Good luck and let us know what the doc says on Tuesday.

Hugs
Gail*Nanners*