After I have been lying down for a while, if I take a deep breath, when my lungs are filled i can hear/feel a gurgle in my lower left back. It goes away very shortly after I sit up. This has been going on for quite some time. I also have extreme fatigue. I have had my hemoglobin and thyroid checked, and both checked out ok. I have also had my lungs x-rayed, but I had been sitting up so nothing was found. They have also done an ultrasound on my left ovary to make sure there were no tumors. I don't know what the next step is to take. A while back I was feeling an irregular heartbeat, they did an EKG and found nothing as well. Could this be an underlying heart problem? I'm to the point where I would like to find out what is going on. I never had this when I was younger, and I am only 28 now.