Tampons and back pain

I have used tampons for 13 years and all of a sudden every time I put one in after about a hour I am getting excruciating back pain. I know I have the correct angle, depth, and size but I am so lost as to why this is just starting?? It’s a sharp pain every once in a while but for the most part it is an extremely intense ache. When I wear a pad BOOM no pain. I don’t mind wearing pads but like tampons for ease of use. Has anyone else experienced this or have any ideas as to what could be happening???