Just started on lexapro

So

I just started taking lexapro today for anxiety and depression. I was prescribed 10mg but told to cut the tabs in half and only take half u til my body adjusts. I don’t know if it’s all in my head but about an hour after taking it my shoulders, back and upper body started to hurt and I keep getting random pains. Anyone else experience this? Of course it’s making my anxiety kick in even harder because I always think upper body pain is a heart attack 🤦‍♀️😩