Please help! Dull throbbing pain ?

I have a throbbing pain that won't go away that is located only on the right on my backside at the bottom/ a little bit below my rib cage. It started last night around 7 and hasn't ceased to stop throbbing. Last night I couldn't fall asleep because I was in so much pain. I even felt a little nauseous but that might be because I have had flu symptoms for the past five days... Not sure if these are related or not.. The pain feels like really bad gas but it doesn't move around... Is this serious? or am I making a bigger deal out of it then i should? Thanks=]