Back ache

I’m 7dpo and have just started getting a pain in my lower back. I’m probably symptom spotting. I know that lower back pain can be a symptom but wanted to ask if anyone could describe what the pain is like? I’m not sure what it is, it could be a knot! Also, I did a medicated IUI cycle and am on Cyclogest pessaries which are giving me headaches, tiredness, some period like cramps and waves of nausea. This is my second month and I didn’t get a back ache last time so thought I’d reach out to the knowledgable people of Glow. Thanks in advance!