Hi, Azithromycin can be taken there is no issue but first of all the reason of the feeling of something struck at the back of throat has to be ruled out. Since you have frequently blocked nose, it can be due to sinus infection or sinusitis or seasonal allergies. Either of these can be a reason of feeling of something struck at the back of the throat. So, first of all, you should consult an Emergency room and get evaluated and a clinical examination and if needed a sinus X-ray and allergy test can be done for confirmation. If there is an infection then Azithromycin can be advised. Do warm saline gargles and antiseptic mouthwash gargles for now and drink warm water. Also, you can use decongestant nasal drops like Oxymetazoline. Take soft meals and plenty of fluids. Hope I have answered your query. Let me know if I can assist you further.