Hardened Tissue Inside Cheeks, Hurts Only When Moving, Swollen. Any Diagnostic Help?

i have a single ball of hardened tissue it seems on the inner sides of my cheeks. After asking my dentist I got told it could be a salivary stone or mucocele. Through my own research, it seems neither fully describe the symptoms correctly. It moves, is pea-sized, hurts only when moving or when I open and close my jaw. I can feel it from the outside over my jaw area by the ear, and can also reach inside my cheek and grasp it. Most saluvary stone description say they are painful and swelling is often present and in my case both re untrue, risng my suspision that it may not be that. Any diagnostic help would be greatly appreciated. Thank you.