What you are describing is called a serous ear effusion. Basically, the middle part of the ear behind the ear drum is connected to the throat by something called the eustachian tube. The eustachian tube works to drain fluid from the middle ear and to equalize pressure between the outside of your body and inside the ear.
Sometimes, especially after a cold or throat infection, the eustachian tubes can become swollen, preventing adequate drainage of fluid from the ear. This buildup of fluid, called a serous ear effusion, can cause some pressure and a sensation of a 'stuffy' ear.
Most of the time, a serous ear effusion will resolve on its own, although this may take a few weeks. It is best not to blow your nose or otherwise try to 'pop' your ears, as this tends to drive more fluid into the ear and make things worse. You could try chewing gum, gargling with warm salt water, or taking an over the counter anti histamine medication although, realistically, these strategies don't work very well and most of the time you just have to wait things out.
To rule out these more serious problems, please discuss with your primary care doctor
. Good luck!