When an earache is the result of an infection it is usually experienced as a sharp or dull pain that can range from mild to extremely painful. Even if the fluid within the middle ear is not itself infected, it puts extra pressure on the eardrum which causes it to throb.
However, if your earache is the result of a cold, there are other symptoms which would indicate it as such. When your earache is the result of a cold, you may have trouble sleeping, exhibit a fever, and display green or yellow mucus when blowing your nose. Since a cold will resolve itself, an earache from a cold will also resolve itself. That being said; earaches can be very painful and distracting and if you feel it is warranted you may wish to visit your doctor to see what the best treatment would be. Paracetamol may be all that is prescribed however they can be easily bought over the counter at any chemist.
It is worth remembering that although earaches can manifest through having a cold, there is sometimes a secondary infection of the middle ear. In this case the ear infection usually comes on suddenly and is very painful in the beginning. This is because the sensory nerves in your eardrum signal the increased pressure with pain. However, after your eardrum stretches a bit, the earache pain may subside.