Swelling may be bad. Retained air in the gut can certainly lead to bloating. However, a "hard" abdomen raises greater concern, such as fluid (ascites) in your abdomen or intestinal blockage. Ascites can be due to significant liver disease, infection, perforation of the gut, trauma to an organ with bleeding, or even cancer. Intestinal blockage, if present, risks rupture, peritonitis, death. Please get evaluated now.
Bloating. As long as no "red flag" signs, such as blood in stool, inability to pass stool, severe pain, or nausea, then this is likely bloating. Bloating is caused by imbalance of microbes in your gut or maldigestion of certain foods. Try 1-2 weeks off all sugars and refined carbs and see if your bloating doesn't improve dramatically. You can also try adding a pancreatic digestive enzyme w/ meals.