Movable hard bump in mouth behind right upper wisdom tooth

I have a hard bump like thing behind my right upper wisdom tooth that has developed 7 months after a tooth extraction. My dental was worked on when I was 12 {content removed} 13 where I had 4 teeth removed behind the K {content removed} 9 to accommodate the growth of my wisdom teeth. I was required to wear braces 2 {content removed} 3 years to make room for the wisdom teeth. A short while back I had the top right 3 tooth from the rear extracted and I have attempted to research online to find information online concerning what this lump {content removed} bump could be. I am experiencing pain 1 {content removed} 3, which when I take 2 excedrin the pain subsides! What worries me is this bump that has developed, which is hard to the touch and movement from left to right is limited. When moving it subsides the pain for a short while but returns slowly without increasing the pain level above manageable without excedrin. There is not visible infection, gum is pink and there is no bleeding or oozing. I did have a metallic task in mouth for a day or two which disappeared. The area of extraction hasn’t closed yet but shows no visible bone, it is pink, just not completely closed. The area in question in the image is on the left upper bump behind rear tooth!