Gall Bladder pain, I am not overweight, eat good, what gives?

I don't understand why I am even having issues. I am not over weight. I eat pretty good, take my vitamens, get exercise. I had a blood test that came back normal. They suspected something with my gall bladder or a ulcer. They put me on Prilocex and I have not noticed any change. I still have pain after eating. Generally do not feel good after a meal. This started all of a sudden a week or two ago. I have no history os gall bladder or ulcers. The pain was comparable to giving birth to my daughter. Anyone know what I should be doing different?