A screenshot of the original image and the jpg would be useful.
But I'm guessing that the jpg is either untagged (no profile), or has the Adobe RGB or ProPhoto profile.
Dont't use Photoshop's Export feature, it strips out the profile, leavig the image untagged.
If you use Save for Web, check Convert to sRGB, and Embed profile.
If you Save As, convert the image to sRGB - Edit > Convert to profile. (duplicate the original first, so you don't have to save the jpg twice)
In general, sRGB is the best profile choice for output, especially when viewing in applications that aren't color managed. (most apps aren't)
Edit: I got the impression that you were exporting from Photoshop, but if exporting from Lightroom, the answer is the same - choose sRGB as color space in the Export dialog.
so change the color preferences in both LR and PS to sRGB from Adobe RGB 1999. I save as from PS, not export from LR. I am just starting to use LR and haven't figured it all out yet.
I was trying to get two samples but I think they would just look the same if I am not looking at it in photoshop or lightroom. I looked at images that I had not adjusted and they look more normal.
>so change the color preferences in both LR and PS to sRGB from Adobe RGB 1999
Do not change the color preference in Lightroom. This won't change anything as the only thing it impacts is the color space that gets sent to Photoshop when you do "edit in Photoshop". You generally want to stay in as wide a colorspace as possible until you export to images for the web when you have to go to sRGB, but that should be your last step.
The reason your images look different in Photo viewer is that it isn't color managed. You need all your apps to be color managed in order for them to show the correct color. You also need to export to sRGB if you send your images to anybody else. That is trivial in the export panel in Lightroom.