Viagra and mav/migraines

Wondering if any guys out there may have any experience with this. I have been on meds for MAV for a year or more and have been taking viagra for ED in this time I have not had any migraines or balance probs after taking viagra, but am a bit worried that the medication is masking the migraine and that the viagra is not doing me any good. Anyone have any ideas. Please message me if you do. Thank you.