Between your middle ear and the back of your throat/nose region there is a connecting tube called the Eustacian tube (spelling might be incorrect). It's job is to drain excess fluid away from the middle ear and to equalise pressure. When you have an upper respiratory infection like you have this tube can get blocked. The trouble you are having is due to excess fluid getting trapped in this tube and causing popping and hearing symptoms. Firstly there is nothing to worry about unless you get an ear ache. Once the excess mucus build-up dries up the whole issue should stop. You could take some medication to help the "drying up" process but if I was you I'd just drink extra water, maybe take some extra vitamin C and do all the other things you do to get better from a cold. Lemon juice in water is said to help clear excess mucus. There isn't much you can do instantly clear the tube (and regain proper hearing) when it blocks... try not to blow too hard as the sudden pressure (I have heard it said anecdotally) can damage the delicate inner ear. Hope it clears for you soon.