It might be related to any vaginal infection
as tampons are often associated with vaginitis
(vaginal infections). Therefore, I recommend to try other alternatives rather than using tampons.
In addition, once your periods are off, go and do an urine analysis, vaginal swab testing and culture to exclude uro-genital problems.
Furthermore, do you have problems with constipation? - if yes, that could explain your problems. Change diet (more fiber, more water), lifestyle (exercise, not being sit all the time) can also help.