Where exactly in the abdomen does it hurt? Is there a bulge where you are hurting? It is also important to know whether or not you have undergone surgeries in your abdomen, prior umbilical, epigastric, inguinal, or incisional hernias before. Presumably that you've never had a hernia
or any prior surgeries in your abdomen or inguinal area, the pain you are feeling is probably a muscle pull. However, a hernia is always possible. You may have had a small non-symptomatic inguinal or umbilical hernia before, and the extra abdominal pressure from the heavy lifting has just made it larger. Abdominal hernias are very common. It is one of the most common reasons for elective surgeries. Depending on your body habitus as well as location of your hernias, it can be very difficult to examine. Therefore, it should be examined by a general surgeon
who sees a lot of patients with hernias because subtle signs can be easily missed. Hernias don't go away on their own and should be corrected because there is a risk for bowel entrapment which can be disastrous. Fixing a hernia when the bowels are not stuck in it is straight forward. There are different approaches to treat a hernia (most are very durable). I would suggest a consultation with a primary care physician
who may refer you to a surgeon who can assess your condition and discuss with you his or her preferred approach.