MBD is metabolic bone disease. This can happen if the cham does not have a source of UVB lighting. Early signs of it are instability while climbing and sometimes grabbing legs instead of vines. If the cham does the leg grabbing a few times a month or year, it's usually nothing to worry about. But if it's doing it everyday, multiple times, it can be a sign of nurilogical damage or mbd (from what I've read).
I'd suggest getting a dripper. Unless you're misting for 15-20 min. 3-4 times a day, the cham might not be getting enough water. I know mine never liked to drink from the leaves much. Prefered the dripping water. You can make one yourself. I used a throughly cleaned and rinsed old 2 liter bottle with a pin hole in the bottom (before I got one from the store, used the bottle for about 3 months) Set it on top of the cage and it will drip thru the screen.
I found this link that has a lot of good info. From looking at it, it seems to have everything correct. /care_sheets/lizards/veiled_chameleon.htm] Click here for the site!
Make sure you have everything set up right. If things don't improve, look for a vet. Right now, to me, it sounds like stress. That could be caused from change, wrong set up, or other pets bothering it (even if they aren't on the cage, even in the same room can stess it).
Most important thing to worry about now is set up and feeding.