Breathing difficulty and headache despite of giving all treatment and normal reports and still having low oxygen saturation indicates many possibilities like 1. Development of rising BP of lungs due to low oxygen saturation, 2. Development of chest wall muscular tightness due to muscle spasm at back or neck leading to inability to take normal deep breaths and etc etc ie. many more causes.
Next Steps
Please visit a Chest Physician and get her evaluated.
Health Tips
Continue home oxygen and ongoing medicines till the current situation gets resolved.