Hello! Thank you for the question on HCM! I appreciate your concern! In my opinion the symptoms you have may be caused by a sinus problem ( a chronic sinusitis). An intracranial tumor can also cause similar symptoms. When you breathe, your intracranial pressure increases. So the fact that your headache is worse during breathing may be a sign of a raised intracranial pressure. I would recommend you to consult with your GP, have a careful physical examination, a blood analysis for inflammation. A brain CT scan may be necessary to exclude the above mentioned possible causes. Hope to have been of help! Greetings! Dr. Aida