Losing photo quality when editing?

Please can someone help me, I have recently taken a few photos at a wedding with my Nikon D7200 DSLR camera.

When I have come to edit the photos the quality on them in the editing software look shocking!

Please can someone explain why this maybe? If I was to look at the the photos on my iPad or just on the standard photo viewer on my PC everything would appear to look okay, but when I put the photos into the editing software the photos seems to look mucky.

The photos are in RAW format and I have tried to use PhotoDirector and Adobe Lightroom.

Lightroom can be set to have a default setting for the various sliders. If your sliders aren't set to 0, then it's applying a preset to them upon import. Speaking of import, check your import settings to ensure that nothing is being done to your images.

But then in your question you mention how the images look fine on different devices which means that your monitor may not be working properly or it's been incorrectly calibrated. Is your monitor calibrated, and if so, what device did you use and when was the last time you recalibrated it? It's very possible that your last calibration actually made things worse.

Define mucky.

Try being sure 1.) The image is in its original RAW form - as Faux suggested, be sure no presets are active. I would re-import the images after being sure all presets are off. Be sure the monitor is calibrated correctly. Lightroom has a calibration tool, but if the monitor is off, the images will be wonky.

2. Use the tone curve to clean up the white and black points - sometimes the grey muck is just the contrast is not set right.

Without seeing what you are talking about it is hard to guess what the problem is.

I'm more a photoshop person than lightroom so that is about all I can recommend without seeing the issues. Maybe post one on Flickr?

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The idea that a Nikon raw image appears ok in PC viewer, and mucky in Lightroom, seems odd, and how did you get raw from camera to iPad, that requires converting to transfer, and if appears ok, should look the same in viewer or Lightroom,

Details in converting from raw to jpg not mentioned, and blur/mucky/ pixeled/ term not clear about what is changed in visible aspect, mucky means muddy, colour dispersed to blended smears, that does not equate,

If Nikon, then try Nikon viewer editor to see what actual image is, and export via Nikon software, and compare with Adobe Lightroom version, they should be identical in base details, better than PC viewer,

If image appears more noises with pixels, that is not murkiness but higher detailing close up, and that is raw dynamic, which requires colour correction and then export to jpg, basic viewer does not adjust RGB to match adobe or Nikon color profiles, not allow depth of colours, that is to do with calibration of photoshop to computer monitor to printer, check those options

You may not have noise reduction set properly in LR.
Other than that, you need to show an example of what the camera JPEG file looks like and what your rendered image looks like. Most likely lack of operator knowledge using LR.