Whenever I try to live color or even color an image after using the Pen Tool to make the outlines, I get this really weird grey colors near my lines.
how can I fix this? Like the yellow coloring seems fine, but everything else isn't.
Overprint, trapping, antialaising, slight variations in the contours. Take a pick. in any case, don't put too much faith in AI's preview. Export to PDF or a raster format to verify integrity of such stuff.