@bear78-- That happens to me too. I too thought that it was an allergy but I looked it up and it's actually because of an enzyme in pineapple called 'bromelain.' This is a tenderizing enzyme, it breaks down protein. That's why it's used to tenderize meat sometimes. Other similar fruits like kiwi and papaya have similar enzymes. This is why they leave a strange flavor in the mouth. They actually start to tenderize our tongue as we eat them but it doesn't result in damage since we chew and swallow fairly quickly.
The strange part is that it doesn't happen to my family members. My mom can eat lots of fresh pineapple and not experience this. So maybe it has a genetic component too. It also doesn't happen from canned pineapple. The canning process removes most of this enzyme.
Having said this, I'm not a doctor. If you suspect allergies to a food, you need to stay away from it. It's possible that you are allergic. You may not have had swelling previously, but what if it happens next time? So please avoid it and see your doctor. You can get tested for various food allergies.