I have been getting bouts of dizziness at various points in my day, and have not been able to pinpoint a cause. what are some possible reasons?

Many: Inner ear or "Vestibular" causes are some of the most common causes. Other causes may be metabolic such as high or low blood sugar, dehydration, electrolyte abnormalities, thyroid diseases, heart conditions, blood pressure fluctuations, etc. etc. If they persist than see a dr. and get a good check-up evaluation. Best wishes.

Many things possible: Defining the word "dizzy" is very important. Are you lightheaded or feel as if you were spinning? Things that can cause either of those types of feelings include low blood sugar, ear/sinus infections, medications, headaches, stress & anxiety, other inner ear problems aside from infection, and others. Your doctor will get a detailed history and decide which of those possibilities is most likely.