Hi and welcome to the forum! I am glad that I can help you.
You want to know the cause of the symptoms that you experience.
There are so-called weak spots on the front abdominal wall where hernias can be formed. One of these spots is the inguinal canal and the vertical lines that cross the umbilicus and the other on nearly 3 cm aside from the umbilicus. Conditions that cause an increase of the abdominal pressure such as weight lifting, pushing or pulling may cause protrusion of the peritoneum or intestines through one of the weak spots.
According to the data that you described, you experience pain in the abdomen. You may experience the pain due to the increased abdominal pressure on the front abdominal muscle wall although a hernia is not formed yet. Avoid any physical activity that causes an increase of the abdominal pressure such as pushing, pulling, or weight lifting.
Please keep in mind that I provide medical information only. I am not able to diagnose medical conditions online. Please contact your doctor for further advice and information about diagnosis and treatment options.