Anyone took estrogen shots before their iui’s?

This is my 4th iui- this round my dr gave me two shots (one one day and then one the next) of estrogen to make my lining better- it was a only an 8.2, so he said it would help make things more cushy. I have never had these shots before. the last one I took was the day of my iui which was 7 days ago. I also had the trigger shot. But my nipples have been so sore since like a day after the iui. Is this from the estrogen? If so, when can I expect it to wear off a little? My boobs really don’t hurt although they feel heavier and larger, my nipples just hurt! They do feel a little better today but not much. 😑 I’ve also had lower back pain on my right side the last two days... praying it’s good signs and not all because of the fertility drugs. But ouch... they hurt.