Each time I get a fill they say nothing but liquids for three days. Why do they say this? Is it possible it will stretch out the band ?

I think it's for safety and get you used to it. My surgeon wants 24 hours liquids, 24 hours mushies and then progress as you're comfortable.

A fill can irritate the lining of your stomach causing the tissue to swell. If the tissue swells, it can make your stoma so small that you experience a stuck episode. That's why you drink liquids. Most docs only require it for 24-48 hours though.