Hi, not sure if this is helpful but I can share my experience from mine. I did my IUI recently and a week later had lower back aches but I think it’s cos I had an infection. My other symptoms were yellowish discharge, fever (started a week later) and abdominal bloating. There was also a increasing pressure on my rectal area when I sat down.
Should not be due to medication. Try to change sleep position and do some slow walking. Hope it helps
christine