Hi there, don't mind me, I was intrigued by this thread because I have Chronic Sinusitis Disease and sometimes I too have dizzy spells. Such as, when I stand up or during exercise my eyesight is blurred and goes completely black for a few seconds or I lose my balance and feel disoriented, along with heart arrhythmias and a tight chest that can occur at rest and during any time (its never specific, nor has it been diagnosed as anything but stress but I'm 20 so I don't necessarily agree with that). So my thought was, have you had your thyroid checked along with hormones and blood sugar levels? After reading @jenniferhunter 's post, since you both used to be very active and fit I would try to remember any little injuries you had at a young age till now( @phillipc421 and @redhead63 ) the smallest injury may not show up unless someone is really looking for it and may show up years later with odd symptoms but no connection to anything because you never thought anything of it or remember it cuz you were so young, specifically any falls or head trauma or broken nose/fight/high school sport injuries or stress fractures. Ask your parents about any odd complaints of pain or discomfort as a child. As a toddler, I used to lay my head on the tile floor and my mother used to ask me what I was doing and I would tell her it felt cool on my hot, pounding head. I then had an MRI but it was cleared and I was sent home with no answers. To this day I'm an absolute mystery box and still have these awful migraines, chronic fatigue and what I think are pressure headaches from extreme compaction in my sinuses (so for all I know I could've had sinus problems since I was born). My ENT at Mayo, who I had met with a few times 2 years ago, wasn't even sure as to what was causing my symptoms but it was severe (I also met with 7 other primary doctors at Mayo all in different specialties). So since nothing has been determined as to what's really going on, I've decided to try pro and pre-biotics again and work on my gut health and start working with other types of treatments such as acupuncture and cryotherapy because I've heard nothing but positive outcomes from it. I've seen a holistic type of doctor in Walker, Minnesota. I think he is extremely intelligent/helpful and goes about diagnosis in a way I never knew was possible and I think it's worth a try for people who feel like there are no answers even from the best of the best! Just remember to keep an open mind and be optimistic, you never know what could be waiting behind the next door. Even if it seems super weird and unfamiliar, it never hurts to try something new, especially if it's about your health.