Hi bluebird68!
Your doctor will prob want to do an abdominal x-ray to see if it's migrated. You're experiencing pain. Expulsion should not be assumed.
You may find this case report helpful:
No visible strings during an IUD check-up [Article in Dutch]
Wendeline C Alderlieste, Jac J W M Jacobs
PMID: 25827147
Abstract
Background: When there are no strings visible during an IUD (intrauterine device) check-up and ultrasound does not show an IUD in the uterine cavity, expulsion is commonly assumed. If the patient has abdominal pain further investigation is advised. This case shows that this policy does not cover every eventuality.
Case description: The patient is a 32-year-old gravida 2, para 2. One month after IUD insertion she developed abdominal pain. The strings of the IUD were not visible with a speculum and ultrasound revealed an empty uterine cavity. Over the next few years the abdominal pain decreased but she developed atypical symptoms that were interpreted as psychosocial in origin. Two years later she presented with new abdominal symptoms and we referred her to a gynaecologist. An abdominal overview X-ray image revealed the IUD, which was removed laparoscopically.
Conclusion: If there are no strings visible at an IUD check-up, perforation of the uterus needs to be considered. An abdominal overview X-ray image, which is relatively cheap and non-invasive, can then easily be taken.