I feel like i need to pop my ears, all the time, & i can pop them at will - i hear the pop sometimes a crackle, but as soon as i swallow it goes back to how it was before. is this normal? or can it mean eustachian tube dysfunction? thank you?

The Eustachian tube links the floor of the middle ear cavity to the back of the throat. It allows middle ear mucus to drain to the throat and air to enter from the throat to the middle ear. What you describe is occasional blockage of the tube, leading to minor vacuum as oxygen is absorbed followed by re-opening after jaw movement-air moving in. Common for some/allergies/colds/ not worth worrying.