Urge to stretch?

So, I'm 6 weeks pregnant with my first baby. I have very few symptoms, really almost nothing and that worries me a bit. But just wondering, when I'm lying down relaxed I get the urge to stretch my stomach muscles. Hands above head and reach back kinda stretch. It's literally the best feeling in the world to me. At 6 weeks there no baby that high up so I can't imagine why I would have this urge. I'm not a work out person, I never did stretches or exercise before pregnancy, this is totally new. Anyone else feel like this? Or explain why lol