i am 27, weigh 195, and am 5 4 . I have a history of ulcers and endometriosis. I just apent four days in the hospital and they told me I had air in the mediastinum. They ran some tests but never confirmed where it came from. They sent me home and said I just have to wait for my body to absorb the air. I have had minor chest pains for 7 years. Also, about a year ago, my pulse was getting really high(160 to 180). Both times, I had full chest work-ups, and they said everything was okay. I still have problems with both, and now this new thing. Do I need to insist that they continue testing, or is it not a big deal? Thanks for amy help.