I am sorry to hear that you have been dealing with a dry throat that repeatedly turns into a sinus infection, and that it has you worried that something might be wrong. It will be hard for me to be able to tell you with any certainty exactly what is going on in your specific case since I am not able to take a history (i.e ask you more questions) or examine you - which is why you should see an ENT physician. In this case I would not only examine your head and neck, I would likely perform a nasopharyngoscopy which is an in-office procedure where a small fiberoptic telescope is used to visualize the inside of the nasal cavity and sinus openings, nasopharynx, and larynx (voice box). This would tell me if you have any active sinus disease, evidence of chronic rhinosinusitis, and whether there are any abnormalities in your nasopharynx and larynx (i.e. throat) that could explain your symptoms. Any ENT (Ear Nose Throat) physician will be able to examine you, take a thorough history, and figure out what is going on with your sinus disease. It is possible that you have seasonal allergies that could be contributing to your sinus infections and nasal obstruction, which the ENT will question you about when you see them. Best of luck.