Most hernias in adults can be confidently diagnosed only by a physical examination.In newborns and infants it is a bit tricky at times.To diagnose a hernia based on the type of pain alone is not mostly possible.
Groin hernias (inguinal and femoral types) may produce dragging pain in the abdomen due to traction on the mesenteries of the large or small intestine or on the greater omentum.Pain at the site of the hernia itself may occur in cases of incarceration or strangulation of the hernia.There is no 'characteristic' or 'typical' pain for any particular hernia.
In most groin hernias, pain tends to be worse in the erect posture and gets relieved on lying down - in your case, the opposite seems to be the case.This is perhaps the only point in your history which is unlike in most groin hernias.
If a groin hernia is not evident on physical examination, but when the suspicion is high,sometimes we request an ultrasonography which may pick up some of these.
Other tests such as herniography,CT scan etc may be useful rarely in the detection of occult hernias.Best wishes!
MB BS, MS, FRCS(Edinburgh)