Men are very susceptible to hernias. Tony's spot on. A hernia is a loop of bowel that slips through the abdominal wall between the muscles. Men usually get one of two types. #1 looks like a tumor at the waistline if it goes untreated #2 feels like your scrotum is full of rice. Neither should go untreated because blood can be prevented from supplying that trapped loop of bowel. That tissue can die and become a massive infection.
#1. Epigastric hernia:
Occurring between the navel and the lower part of the rib cage in the midline of the abdomen, epigastric hernias are composed usually of fatty tissue and rarely contain intestine. Formed in an area of relative weakness of the abdominal wall, these hernias are often painless and unable to be pushed back into the abdomen when first discovered.
#2. Inguinal (groin) hernia: Making up 75% of all abdominal-wall hernias and occurring up to 25 times more often in men than women, these hernias are divided into two different types, direct and indirect.
Both occur in the groin area where the skin of the thigh joins the torso (the inguinal crease), but they have slightly different origins. Both of these types of hernias can similarly appear as a bulge in the inguinal area. Distinguishing between the direct and indirect hernia, however, is important as a clinical diagnosis
http://www.emedicinehealth.com/herni..._em.htm#Hernia Overview
Hopefully it's just a groin pull. Good luck.