It sure sounds like there is unfilled space there between the inlay and the tooth.. I would present to the dentist and let him/her know . This may not show on x-ray, so I would keep a close eye on this.. it should be replaced in short if this persist.
hope this helps.
To see what I am talking about regarding the photos, go to this link and you will be able to see some before and afters or inlays.
http://www.top3dentists.com/pages/general