Ay, alam ko yan feeling mo mama, lalo na first baby kaya nag-aalala ka ng onti! At 28 weeks ang body mo talaga ay nag-adjust ng husto, so chest pain and back pain together is pretty common, ang uterus mo lumalaki na talaga at nag-push sa lahat ng organs mo, kaya nararamdaman mo yung pressure doon. A few of us mums experienced the same, especially kapag nakatulog na lang or naka-certain positions. Since okay lang ang breathing mo when you're sitting up, that's a good sign, pero since may sikmura pain din, mas maganda pang mag-check ka with your OB lang to be sure, hindi ito emergency pero basta confirm with doc para mapakali ka talaga at sure na everything's okay with baby mo.