In CMYK mode, I am seeing what my print colors actually look like, correct ?? I'M trying to brighten my pictures.

Predictable "soft proofing" of color on the computer screen partly depends on the color management setup on your computer. Color settings can be found in the Edit menu of either application. A properly calibrated computer monitor also helps. The other obvious variable is the kind of printer being used.

Generally colors in CMYK are going to be a bit more muted than RGB colors, but the colors will print within the gamut range of the printer. The RGB color range goes well beyond the limits of CMYK.