i was discussing this with my provider a couple of weeks ago as they believe my band is leaking, I asked them if it was possible that I didn't have restriction because my band had moved, they explained that if it had moved the usually symptoms are pain behind the breast bone, inability to eat, swallow and digest, acid reflux, heartburn and associated pain. And if a defill doesn't eliminate these symptoms ;they are often a sign of over restriction too, then they would investigate possibilities of it having slipped.
What makes you think yours has slipped and have you spoken to your provider?
If you've recently had a fill, if could be a sign of over restriction as acid reflux and heartburn us a very common sign. Try bland foods and liquids to see if it settle, assuming you're able to eat and drink ok?