Hello , very apt presentation of your symptoms.
Noted above history and I can say that as it was a pollination period all allergy related symptoms of nasal inflammation,causing chest congestion and breathing problems,and for which longer than normal dose of medication may be prescribed.
Next Steps
No harm in taking the anti allergic medication.
Health Tips
Suggest-to rule out other causes like eosinophils,cXR and lung function test from chest physician will help.
You can also open an online chat app for further guidance.