I would like to have 3 columns in a section, how can that be done? I know I can shrink cells, but can't get them to line up next to each other

Please check this guide to learn how to position fields in your form: http://www.jotform.com/help/328-How-to-Position-Fields-in-JotForm

If you want more fields to be in the same line, you might need to also increase your form width from Preferences>>Form Styles>>Form Width.

Let us know if you need more help.

I did change the width, but then noticed that the page did not look right on a mobile device.

I cloned the page for the phone/tablet and improved it, but it is still not 100% correct.

when I cloned it for the phone, changed the width back, still not 100%

It seems that the form is not enabled to be Mobile responsive. Please refer to the guide below that can help you in making the form Mobile responsive.

http://www.jotform.com/help/311-How-to-make-Forms-Mobile-Responsive

Hope this information helps! Please get back to us if you need any further assistance. We will be happy to help. 

I have 2 forms - one is specifically for the mobile device and I did make it mobile responsive.  It is called Clone of LLL Puppy Application iPhone

What is the form you are referring to? Our forms are optimized for mobile views, however, when the forms are edited(like form's width increased), it's recommended to activate the mobile responsive features. Please give it a try and let us know if you need more help.