Reaction to Fruits and Veggies?

I have been fine with fruits and vegetables all my life. Now, it seems every time I have a fresh fruit or vegetable, I get this weird feeling in my throat and deep in my chest. It's a painful sort of pressure, and it makes it very uncomfortable to swallow. I also get a nauseous feeling. Specifically, this has happened with carrots, apples, tomatoes, and peaches. Does this sound like an allergy or something more serious? What could this be?