My implant tooth doesn't move or feel loose but it seems to have shifted over the years. Any suggestions?

I have had an implant tooth for 10plus years and it seems to have moved closer to anther tooth. There is no gum discoloration but the tooth next to it is a different shade then the rest of my teeth. Also I have been having some tooth pain and pain in my nostril right above the implant. My former dentist has since retired and closed practice so I'm not quite sure how to handle this.