As you are sitting there reading this. Shut your mouth, squeeze your nose shut, and slowly try to blow air out your nose. As the pressure in your throat rises, you'll hear( and feel ) your ears pop. They just equalized to the pressure. As you go deeper the pressure of the water is trying to push into the lower pressure of the space behind your ear drum. If you equalize the pressure in your ears about every 8 to 10 ten feet as you go down there should be no pain. If you still have pain, see a specialist.
There are clubs and courses for free diving in Toronto.