As Dan said you can get the frequency list anytime whilst at your departure airport by using Hotkey #3. This was added in update 3.10.12 and was documented in the Version History.PDF which you will find in your PF3\Help folder. It's a really good idea to check this document for each update to ensure you are aware of all the latest features and it is usually more up to date than the User Guide.
Regarding your Ground frequency issue, I don't know where you're getting your information but the default P3D Ground frequencies in P3D are 121.70 and 121.90... PF3 will usually use the first one in the list. These may also be changed slightly if there are any clashes with other frequencies. If the ground frequency you were handed off to was NOT 121.70 then I would need to see the Debug_Monitor.log file please, which you can zip and attach to your post. If you've completed another flight since reporting this issue I will need to see the OLD_Debug_Monitor.log file, but if you've completed two or more flights since the issue the information will now have been overwritten, in which case it would be quite easy to recreate and then attach the log.