What you see on your monitor is RGB. Yes, it's a CMYK file, and it's likely trying to compensate, but it's still using an RGB model.

As such, what you see on screen is usually always more vibrant/saturated than what CMYK can produce. This is due to the reproducible colors being different in each color space: 



Using coated paper and/or applying a top-coat can certainly help your CMYK print look brighter, but ultimately, you are at the mercy of what CMYK can do. 

At this point, you need to talk to your printer and get their feedback. They may be able to tweak the file to accommodate. Alternatively, if it is yellow that is the issue, perhaps they can swap Y for a more vibrant Pantone Spot Yellow. 

How to increase saturation or intensity of this printed pattern
Should I just pull the plug?  Or is it best if I exit LXDE and any other running processes first?
