Oh awesome, that is a good thing! :)
You have the ability to see your chakras, which is pretty amazing as it is, but if you can control the sensation and pull it down, this makes me think you may have started the process of kundalini. That is very cool, although said to be rare, because my kundalini started at the third eye as well (in reality my third eye was open since childhood, but just intensified suddenly), although by itself, then it moved up, then down, then up, then down, now it just goes everywhere.
Well i guess, with me, and most, kundalini happens, usually all the time, but it seems you are beginning to feel it.

Oh, don't worry, when the energies begin they can feel unpleasant only because we are not used to it, headaches and such, are just the energies working their way through slight blockages, which is a good thing. Pressure, and all those feelings are just the feelings of the energies working.
You may feel other annoying side effects eventually, but as time goes by, the sensations begin to feel very pleasurable, almost orgasmic hehe. When i was first starting out with it, i had the tendency to flinch and try and stop it from moving, because my body wasn't used to it, and because it kind of scared the **** out of me lol. But you've only been doing this a short while, so just know, it starts to feel a lot better, amazing even. The more you focus on the energies the more powerful they will become, at least in my experience.

Keep trying to move it downwards because that can be an easier way to feel your other chakras, and also try to expand it to the crown (if you wish), just a slight warning that kundalini side effects can be kind of annoying in the first stages, such as nausea, disorientation, extreme sensitivity to all energies around you, and do not be alarmed if you get side effects that seem medical related, they are not, but it brings on the most amazing spiritual awareness, and spiritual abilities. The third eye is supposed to bring out psychic abilities, and help you to see auras and such!
You mention you cannot hold onto it long, it's just focus. If the current ends up at a point and hammers away at it, you might have a blockage that needs some assistance in that chakra, but usually when the real flow of kundalini happens, it gets through it no matter what, which can be unpleasant at first to experience, but i highly enjoy the intensity of it now. Personally my throat chakra is in pretty bad shape from smoking so much, so i always have blockages there, and my kundalini hammers against it like lightening bolts, then tears through it. It feels cool now, but in the beginning i wasn't so pleased.