Cliffy, depends on what type of hernia.
I had a 'sport's' hernia, just above my navel. Had it for 10 years and got it through overdoing stomach crunches in the gym.
if its this, no problem for you whatsoever. I did weights and running for years with no effect.
just got it sorted late last year, in and out in a day, and was running again within three days.
If however its lower down in the base of your abdomen. I think called an Inguinal hernia, then unfortunately the doc may be right.
cheers.