I went in once for that excruciating "referred pain" in my shoulder/lung...they poked and prodded my liver and said that it didn't feel swollen, but gave me a blood test for liver enzymes, just in case. I believe that, if you have liver issues, the test will be that simple to determine it, so you can always go to your doctor and see.
Do you have a doctor who is open to fasting? It would be wise to advise him/her, as it will likely help them to understand the situation should it just be gastrointestinal. If you're concerned about the degree of swelling though, don't leave the doc's office without getting the tests necessary to assure you that no issues are being had in your liver.