Thank you for the query.
Yes, it can be a hernia
. Especially if you lift heavy objects (on the gym), this could cause a hernia. Usually hernia is more visible when standing and coughing (increased abdominal cavity pressure can protrude intestines out). The lump should be less visible when lying down.
Usually hernia contains fatty tissue, however sometimes an intestine can stuck inside causing bowels problems including an obstruction.
That is why I suggest you to visit your doctor and have simple abdominal ultrasound
Hope this will help.