Please help

Mari

Everytime I stretch, like arms over the head yawning my stomach muscles hurt. Like I’ve been working out for weeks(I don’t work out at all for this reason). I went to the doctor and he did a blood test which was negative. But every person I asks say it sounds like pregnancy. I am super bloated though. If I was pregnant I’d be 5+5 days. I had 3 faint positive pregnancy test last week. So I’m more confused. But I just need to know what this stretching thing could be. Please feel free to give me advice while your at it. Thank you.