If it's on the right hand side (approx one fist size from the middle) right under your rib, - then it could be a gallbladder attack. This could be triggered by to much fat (hot dogs) and also mustard/spices. When I had the attacks I could feel my gallbladder as a hard lump. I had the f... thing surgically removed a year ago, never had such problems since. Hot dogs, mustard and coffe was a trigger to attacks for me. And hard digestible vegs, - as carrot !! It can be different for different people. Have also been told LC'ing and the correct combination of foods stops attacks. Wish I knew then....

4 -10% should come from Carbs ( no more than 20g of Carbs)
25 - 30% should come from Protein
65 - 70% from FAT

I agree with the others, consult a doctor to be sure - ASAP !