What makes me think this is, yesterday, the pain was so bad I couldn't take a deep breath to cough. This made me think the pain might be respiratory related. Immediately, I thought about the flowers. So, I put them outside last night.
When I got up this morning, well before anyone gets up or the day care kids arrive, I opened the windows and turned on the ceiling fans to flush the air out of the house. Hopefully, this will make a difference.