+ 1 on the advice above.
Don't feel you need to give up on pads: they do work decently in a hammock, and give you the option of ground sleeping if you need it. But you've already found out that you need adequate width at the shoulders or else you freeze!
Some folks go with a relatively short closed cell foam pad- basically covering from their shoulders down to mid-thigh or so. The other great hint you'll find in these forums is the SPE (segmented pad extender.) Check out Jeff's page on them: http://www.tothewoods.net/HomemadeGearSPE.html
And, welcome to the world above ground!