What Causes Abdominal Pain On The Right Side?

About 21 years ago, I experienced severe abdominal pain on the right side. Nothing leading up to the pain, it just started and I doubled over. Me and my step-brother were in the back yard, I had just come outside, and he was talking to the neighbor next door (mid-aged woman) about our park league baseball team as I started to double over. He kept telling me to get over there and was intent that there was nothing wrong. I tried but I could not stand up. Finally I noticed that upon trying to get up some pain was relieved when my right hand was on my right knee (both hand and knee had to be tensed or it would hurt). So I slowly managed to get back on my feet but had to stay bent over and had to keep tensed. I joined the laughs a little as I wobbled a few feet. The pain slowly subsided over the next 24 hours but that night I remember going to wal-mart and my dad had to cradle carry me, couldn't walk or be held differently. Is there any chance of being food poisoned?