No idea if the meter is reading correctly. 5 or 10 kV is absolutely reasonable for that situation. You've got the better part of a Van de Graaf generator there. Don't forget the voltage generated when your butt shifts or sits up from your chair, either!
If you don't have an ESD strap and all that, make a habit of always touching parts by their ground first (or anywhere else that ESD will spread out reasonably safely from), and only then, handling them freely, or plugging them together.
Good example, say, building a PC: touch the metal enclosure first, then while touching that, touch the expansion card's bracket, then pick up the card and plug it in.
Bad example: grabbing the expansion card in the middle, or by the edge connector or any other vulnerable area, then plugging it into the PC where potentially, your body's charge gets shunted to enclosure (and if the enclosure is grounded, to ground ultimately as well) when the bracket makes contact, or when the edge connector plugs in. If your body happens to be dangerously charged at this point, the resulting zap will probably rip through two or more IO pins on the board(s), likely damaging one or both.
Note that it doesn't matter if your body, or the enclosure, is Earth-ground. Voltage is just a difference. Earth-grounding is used commercially because it's less risky to get everyone and everything grounded to one potential, than it is to have them ensure their potentials are matched before interacting.
Tim