Sulfites

Hi everyone, I'm brand new to this and would like some advice regarding sulfites. I get big spots pop up when I have tap water, headaches, dizziness, cramps and awful joint pains. Would like a bit of advice regarding fruit and veg, does the bagged fruit and veg from supermarkets contain them? Can washing them remove sulfites or will it be absorbed into them? Also does pure citric acid have them? Very confused and need help to get better x