Using a nasal spray (like Afrin) can shrink the membranes in the nose and throat, opening the pathway to the ears. Note: Use these sparingly, as long-term use can cause "rebound" congestion.
Sometimes the physical structures around your ears just need a little manual stimulation to shift. how to clear ears after flight
This is the safest method for sensitive ears: Using a nasal spray (like Afrin) can shrink