My first thought is eustachian tube dysfunction.
The eustachian tube connects the nose, middle ear and throat. Its purpose is to drain any infection or mucus, to stabilize air pressure behind and in front of the eardrum, and to help air flow.
Sometimes, the tube is blocked, or does not open as it should. Then, you get that "bubble" feeling, some hearing loss (temporary), dizziness, ringing in the ear, feeling of fullness. As it improves, you can get popping noises or sensations in the ears. It may last a few weeks.
Causes can be getting over a cold, sinus infections, allergies, air plane travel.
Most of the time, no treatment is needed. Sometimes, sucking on hard candy or chewing some crackers will help open the tube. Decongestants and antihistamines may help, such as Sudafed, etc.
If you find the symptoms are increasing or worsening, you need to seek help from your physician.
I hope this was of help to you. Please let me know if you have any further questions or concerns.