Uy, I understand ang worry mo! But please go to your pedia agad or to the ER to talk about this, hindi ako makakapag-advise sa X-ray and medical stuff like this, lalo na sa ganitong sitwasyon.
Your pedia knows best kung bakit kailangan ng imaging for your baby, so trust that assessment. A few of us mums have been through similar concerns with persistent phlegm din, at laging important ang follow-up sa doctor. Hang in there, you're doing the right thing by bringing her back.