I’m referring to when you hold Shift and move the mouse to position your model to face a direction/axis. Something is ‘off’ with it, so whenever I do it, my model snaps in a diagonal position instead. Is there any way of setting this back to normal…?
EDIT: Thinking about it, it’s probably due to me rotating the character at one point or another. >_<
That would be my guess as well.
I’m not sure if it’s related, but using Symmetry to add an InsertMesh so it’s mirrored on either side isn’t working properly. It’ll appear in the right place on the right, but on the left, it’s completely off point and may face the wrong way. And that’s with the X axis selected as well as mirror.
Please upgrade to the most up to date version of Zbrush. It’s free for registered users to do so, and we can’t troubleshoot effectively if we have to factor in possible issues with obsolete versions.
Your issue here seems to be that your mesh has been moved off-center in the worldspace.
Depending on what has happened, you may be able to fix this by resetting the sliders in Tool > Geometry > Position to 0
If you have no demands on the objects scale from other programs (doesn’t need to match dimensions someplace else), you can also fix this by using Tool > Deformation >Unify.
If you have multiple subtools, you can use the Tool > Deformation > Repeat to Other command to repeat this across all subtools, but it may result in variances in scale across the subtools. To avoid this you would need first merge the subtools before re-centering, or use Transpose Master.
[edit]
To add to the above, if you have not corrected the rotational problem from earlier in the thread, your mesh may be out of rotation still as well, and unifying the scale/re-centering will not fix this issue.
It may be at this point that your tool is so out of whack for whatever reason, it will be impossible to simply move back into symmetry. If you cannot Undo your way out of this problem, or restore an earlier file, you will have to force mirror the symmetry.
To do this, switch on all three planes of the floor grid as a visual aid, and move the mesh as close to the center line as possible. If it is out of rotation, rotate the mesh back into position as well as you can. Then, use Tool > Geometry > Modify Topology > Mirror and Weld along the appropriate axis (typically X for a character mesh).
This may result in some seam issues along the middle in the resulting mesh that will need to be smoothed out. The more closely the mesh can be eyeballed into position, the better.
This did the trick! Thank you. 
Wouldn’t you know it, I now have another issue. I made a InsertMesh to add to my character model, but when I select the character, he darkens and one of the InsertMesh Tools is selected instead. So whenever I try to move the character, it’s the InsertMesh that’s being moved. It isn’t a Subtool in the Subtool menu, so I can’t merge it.
What you’re describing sounds like the normal operation of an Insert Mesh brush. IMs are inserted as part of the selected subtool.
When you use an IM tool, it auto-Masks all the geometry in subtool except for the newly inserted mesh. This allows you to freely position the new mesh without affecting anything else, even though it’s part of the same subtool. When you’re happy with its position, you can clear the masking via Tool > Masking > Clear, or by CTRL-dragging a marquee in empty canvas space, and releasing it.
If you want to split that mesh into a separate subtool, while the rest of the mesh is still masked, go to Tool > Subtool > Split, and select “Split Unmasked Points”. This will move the unmasked Insert Mesh tool into a new subtool.
Ahhh, of course. Masking. Makes sense. Thank you.
