much of the info is in this sticky thread-
Trigger point information {TrPs} for short
http://neurotalk.psychcentral.com/thread125577.html
post #1 in it has a collection of info links

this is one of my favorite ones for locating TrPs -
http://www.pressurepointer.com/pain_reference_chart.htm

You just find Arm Pain and click the list below it and read about each & the symptoms , also has a photo with highlights to show where pain is referred to and shows the muscle & where to feel for TrPs...

Same for Hand pain..etc