Why am I so sore?

Im 37 weeks and from the middle of my back down to my butt and my entire stomach is so sore I can hardly move and I haven’t done anything? I was just walking through Walmart and it started and hasn’t stopped yet, I can’t get any relief 😩 I had a fever last night and my throat is sore so I thought maybe it was The flu or a cold so I took some Tylenol and a couple hours later my fever broke and I woke up drenched in sweat and my throat feels slightly better but these sore muscles are gonna be the death of me 😭😭