Sorry, I didn't mean to panic you! My pal had that for ages and she wouldn't go to drs cos she was worried she had lung cancer (she's a chronic worrier) and I kept telling her about her stomach. She eventually went and was diagnosed with an ulcer, but if she'd gone earlier they would've done the test for helicobacter pylori and could've given antibiotics and antacids and she would've been fine, but she had left it too long. It could just be your shoulder though...