A year ago i was bitten by what i think was a deer tick in my belly button. i have a scar. occasionally the area swells and itches. is this normal?

Not really: What you describe sounds fairly mild (occasional swelling and itching), but it is not normal. Typically if the "bite" was infected, the symptoms would not be so intermittent, and it would be tender. However, "something" is irritating your skin. Since it has been going on for a year now, it may be time to see your Dr or a dermatologist the next time it swells up. (I wouldn't go when it's normal)