What causes pain a year after the extraction/bone graft?

Ordinarily any bone graft procedure performed with any approach that enhances local regenerative (healing) response has less postoperative pain than if done without it. The fact that you experience pain and discomfort is an indication that there is something going on with...

Pain can be indicative of inflammatory process or infection (peri-implantitis). This is not normal after 3 months and it should be evaluated by a surgeon to assess its health. See link below for more on this condition.

That looks like your own tooth. You might have had a post and crown and now they have come out. You should remove the tooth and have implant. The cost is about 4-5k

Removal of a dental implant can vary depending on what bone regenerating procedures have to be done in conjunction with the removal. Also, it's important to note whether a new dental implant will replace it. Dental implant removal can be anywhere between $500 to $1,000. However, keep in...

I can't really tell from the photo, but if the white material is hard to the touch it is most likely a piece of bone graft material. The more important question is whether there is a fistula, which is a track that originates from a point of infection out into the mouth for drainage. Please see...

Your dentist is correct, over time you will get some bone resorption and if you were ever to proceed with an implant you may have to regraft it.