Goiter and thyroid question?

I’m a 22 year old female and have a goiter. My doctor first mentioned it to me when I was about 16 and again last year.

I’ve had my TSH tested regularly as well as Free T3 and Free T4, all are normal. I have symptoms that could be suggestive of a thyroid problem but are being treated as a connective tissue disease (Lupus/Sjogren’s overlap). I’m on Plaquenil and have improve dramatically. My GP felt my goiter and said she can’t feel any nodules.

My grandma has a thyroid condition (don’t know which one but she take levothyroxine. I have a number of autoimmune diseases in my family and I also have Celiac Disease.

Is it possible to have a thyroid condition and have normal blood tests? Should I have it tested regularly?

(2blest, please don’t post your usual copy and paste answer, I’ve read it before =] )