What Causes Constant Bloating In Abdomen?

My stomach is sometimes bloated and it hurts. I have irritable bile. I think it is something more. Some days it hurts so much I can t function. I m afraid that it might be stomach cancer. Cancer has killed off the first two generations of my family and it is now killing off my (third) generation. We have had breast, colon, lung and prostate cancers. Could this be my issue? I am afraid .