Did you get water in it in the shower? Pour (or have someone pour) some rubbing alcohol (about a half cap full) into your ear, let it mix with the water for a minute, then turn your head up or to the side, shake and let it drain out. The alcohol content will cause what water is left to evaporate. I do this when I swim and get swimmers ear.
If it is painful - DON'T DO THIS! You may have punctured your eardrum! In that case, go see your Dr.
You might be slightly congested. If your having allergy issues or have been sick you with a lot of pressure in your head you might want to look into taking a decongestant. They also sell ear drops to help loosen up built up ear wax you can also use hydrogen peroxide. Lay on ur side and let the hydrogen peroxide site in your ear for 5 minutes turn over onto a wash cloth and repeat for the other ear.
The water can be deeper in your ear to the point where you can't detect moisture outside of it. If you can recall why you might have water to begin with - like swimming or showering, you might try the "bounce" thing (sounds silly, but it can work) or buy drops at CVS that alleviate trapped water from the ear ("Aqua-Ear" comes to mind) If no success, you very well might have an inner ear infection. Check it out with your doctor.
I had the same sensation for about a year. Then I found out I had high blood pressure. Almost immediately after starting on my HBP medication, it went away. Check your blood pressure and see if it is high, if so, see your doctor.