Been there, done that, many times. What you have is too much wax built up in your ears, and as it shifts around in there, it's sometimes blocking your eardrum enough to affect your hearing.
And yes, you can treat it yourself! Go to the drugstore and find the eye-and-ear section. There's a product called... hmmm... I can't remember the name, but it's a smallish white box, and inside is a little squeeze bottle of eardrops and a small plastic syringe (not the kind you give a shot with -- this is just a little bulb with a long pointy tip).
What you'll do is apply the eardrops as directed, probably several times. As you do, the wax will melt and bubble and shift some more, and for awhile, your hearing may be even more blocked than before. Then, when you feel everything in there is softened and ready, you'll run a bowl full of very, very warm water and use the little plastic syringe to flush the water repeatedly through your ears. The excess wax should come out easily. (And if you do this once a month or so as a preventive measure, you should have no further trouble.)
Afterward, you may want to dab some Vaseline in your ears, because they'll be a little bit raw and itchy from the drying effect of all that water.
If this doesn't work the first time, you can try it again... or, if you feel the problem is just too severe to respond to home treatment, you can ask a doctor to "irrigate" your ears. A nurse will probably do it, actually, and she'll use an instrument that looks like a cake decorating tool -- it can deliver higher water pressure than the syringe you use at home. WARNING: Be very, very sure you trust the person who does this for you! If done correctly, it's no problem... but if too much pressure is used, you could have permanent damage.
Surprisingly, irrigation doesn't hurt. But be careful when you start to get up afterward -- the water pressure TOTALLY destroys your equilibrium for a few minutes, and you WILL fall if you get up too soon!
I wish I could tell you the brand name of this product, but you won't have any trouble finding it. It's the leading brand, very common, and it's the only one I've ever seen that comes with the little syringe. Good luck!